Bsi bs 3a 125 to 3a 132, 3a 136 to 3a 143, 3a 147 to 3a 168, 3a 180, 3a 181, 3a 186, 3a 187, 3a 192, 3a 193, 3a 200, 3a 201, 2a 213 to 2a 216 1981 + a1 2013

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BRITISH STANDARD AEROSPACE SERIES

Specification for

Stiffnuts (Unified
threads) for aircraft

ICS 49.030.30

BS 3A 125 to
3A 132, 3A 136
to 3A 143, 3A
147 to 3A 168,
3A 180, 3A
181, 3A 186,
3A 187, 3A
192, 3A 193,
3A 200, 3A
201, 2A 213 to
2A 216:1981
Incorporating
+A1:2013

Corrigendum No. 1
and No. 2


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 193, 3A 200, 3A 201, 2A 213 to 2A 216:1981
216:1981+A1:2013

BS 2870, Rolled copper and copper alloys. Sheet, strip and foil.
BS 2874, Copper and copper alloys. Rods and sections (other than forging
stock).
BS 3488, Technical anhydrous lanolin.
A 102, Steel bolts (Unified hexagons and Unified threads) for aircraft.
A 104, Corrosion-resisting steel bolts (Unified hexagons and Unified threads)
for aircraft.
A 169, Aluminium alloy bolts (Unified hexagons and Unified threads) for
aircraft.
B 11, Brass bars suitable to be brazed or silver soldered.
L 80, Sheet and strip of aluminium-21/4 per cent magnesium alloy (soft-0).
L 81, Sheet and strip of aluminium-21/4 per cent magnesium alloy
(three-quarter hard-H6).
L 163, Specification for sheet and strip of aluminium-coated
aluminium-copper-magnesium-silicon-manganese alloy (solution treated, cold
worked for flattening and aged at room temperature)
(Cu 4.4, Mg 0.5, Si 0.8, Mn 0.8).
L 168, Specification for bars and extruded sections of
aluminium-copper-magnesium-silicon-manganese alloy (solution treated and
artificially aged) (not exceeding 200 mm diameter or minor sectional
dimension).
S 80, Specification for high chromium-nickel corrosion-resisting steel billets,
bars, forgings and parts (880–1 080 MPa; limiting ruling section 100 mm).
S 92, Carbon-manganese steel (suitable for welding).
S 95, 11/2 per cent nickel-chromium-molybdenum steel.

S 112, Semi-free cutting carbon steel, bright bars for machining (primarily
intended for the manufacture of nuts).
S 113, “40” carbon steel bright bars for machining (primarily intended for the
manufacture of nuts).
S 114, Manganese-molybeenum steel.
S 117, 1 per cent chromium steel.
S 137, Specification for high chromium-nickel corrosion-resisting steel bright
bars (free machining) (880–1 080 MPa; limiting ruling section 70 mm).
S 154, 21/2 per cent nickel-chromium-molybdenum steel billets, bars, forgings
and parts (880–1 080 MPa: limiting ruling section 150 mm).
S 510, Carbon steel sheet and strip (430–540 MN/m2) (suitable for welding).
S 511, Deep drawing carbon steel sheet and strip (280–400 MN/m2) (suitable
for welding).
S 526, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(titanium stabilized: 54 hbar).
S 527, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(niobium stabilized: 54 hbar).
Amendments/corrigenda issued since publication
b) Ministry of Defence specifications
AD
114,
requirements, qualification
Amd.
No.DesignDate
Commentsapproval tests and acceptance test
for AGS 2000 series stiffnuts (BA and BSF threads)2).
C1
February 2010
DEF 151, Anodizing of aluminium and aluminium alloys.
DEF

PX-1,
dyed and undyed.
C2 2331, Protective
February
2010
DEF STAN, 03-8 Electro-deposition of tin.
A1
May 2013
See Foreword

This British Standard, having
been prepared under the
direction of the Aerospace
Standards Committee, was
published under the authority
of the Executive Board and
comes into effect on
30 June 1981
© The British Standards
Institution 2013
Published by BSI Standards
Limited 2013

Draft for comment
13/30275817 DC
ISBN 978 0 580 81451 8

iv

2)

Referred to in foreword only.
© BSI 2010


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A213
201,
to 2A 216:1981
3A200,
193,3A
3A201,
200,2A
3A 193, 3A
to2A
2A213
216:1981+A1:2013

Contents
DEF STAN, 03-9 Electro-deposition of silver.
Page
Foreword
iii
DTD 10, High nickel copper alloy sheets and strips.
Section
1. General
requirements

DTD 417,
Lubricating
oil, aircraft controls: anti-freezing.
1 DTDScope
1
904, Cadmium plating.
2 c) Society
Definitions
1
of British Aerospace Companies (SBAC) publication 3)
3 RS 732,
Design
and dimensions
2
Manufacturers
identification monograms for aerospace fasteners.
4
Material
and
manufacture
2
This publication does not purport to include all the necessary provisions of a
5
Freedom
from
defects
3
contract.
Users are
responsible

for its correct application.
6
Protective coating
3
finish
Compliance
with a British Standard does cannot confer immunity
7
Screw threads
3
from legal obligations.
8
Squareness of face of thread
3
9
Identification and marking
4
Section 2. Inspection and testing
10 Qualification approval
6
11 Production batch acceptance
6
12 Inspection of samples
6
13 Testing of samples
6
14 Test bolts
7
15 Torque test
7

16 Bolt tolerance test
7
17 Endurance test
8
18 Torsional strength test (anchor nuts and stripnuts)
8
19 Thrust test (anchor nuts)
8
20 High temperature test
8
21 Low temperature test
9
22 Pressure test for cap nuts
9
Appendix A Equipment for testing stiffnuts
21
Figure 1 — Marking on hexagon stiffnuts
4
Figure 2 — Marking on stripnuts
4
Figure 3 — Marking on corrosion-resisting steel hexagon nuts
5
Figure 4 — Marking on corrosion-resisting steel anchor nuts
5
Figure 5 — Identification of brass or bronze hexagon nut
5
Figure 6 — Squareness gauge
22
Figure 7 — Torque-testing machine
24

Figure 8 — Thrust-testing machine
26
Table 1 — Tolerance on squareness
4
Table 2 — Unscrewing torque
7
Table 3 — Torsional strength (anchor nuts and stripnuts)
and thrust test loads (anchor nuts)
8
Table 4 — Materials for stiffnuts (Unified threads) for aircraft
10
Summary
pagestypes and British Standard numbers, with
Table 5 — of
Stiffnut
temperature
11
This
documentclassification
comprises a front cover, an inside front cover, pages i to vi,
pages
and a backand
cover.
Table16to—31
Dimensions
part references of ordinary and
thinstandard
hexagon has
stiffnuts
125 to(see

A 132,
A 180 and
A and
181)may have had
12
This
been (A
updated
copyright
date)
Table 7 — Dimensions
andThis
partwill
references
of hexagon
amendments
incorporated.
be indicated
in the amendment table on the
cap nuts
(Acover.
213 and A 214)
13
inside
front
Table 8 — Dimensions and part references of ordinary and
thin double-lug fixed anchor nuts (A 136 to A 143, A 186 and A 187)
14
3) Obtainable

from the Society of British Aerospace Companies, 29 King Street, St. James’s,
London, SW1.

© BSI
BSI
2010
©
The 2010
British Standards Institution 2013

vi


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 193, 3A 200, 3A 201, 2A 213 to 2A 216:1981
216:1981+A1:2013

BS 2870, Rolled copper and copper alloys. Sheet, strip and foil.
Page
BS 2874,
Copper and and
copper
alloys.
Rods and
sections (other
Table
9 — Dimensions

part
references
of double-lug
fixed than forging
stock).cap nuts (A 215 and A 216)
anchor
15
BS
3488,
Technical
anhydrous
lanolin.
Table 10 — Dimensions and part references of ordinary and thin
double-lug
floating
(A 147and
to AUnified
156, A threads)
192 and A
16
A 102, Steel
bolts anchor
(Unifiednuts
hexagons
for193)
aircraft.
Table
11Corrosion-resisting
— Dimensions and steel
part bolts

references
of ordinary
A 104,
(Unified
hexagonsand
andthin
Unified threads)
single-lug
fixed anchor nuts (A 157 to A 164, A 200 and A 201)
18
for aircraft.
Table
12
—
Dimensions
and
part
references
of
ordinary
and
A 169, Aluminium alloy bolts (Unified hexagons and Unified threads) for
thin
stripnuts (A 165 to A 168)
19
aircraft.
Table 13 — Calibration of spring balances for torque and
B 11, Brass bars suitable to be brazed or silver soldered.
torsional strength tests
23

L 80, Sheet and strip of aluminium-21/4 per cent magnesium alloy (soft-0).
Table 14 — Dimensions for high limit and low limit test bolts
25
1
L 81,15
Sheet
and strip of
aluminium-2
/4 per
cent
magnesium
Table
— Acceptance
gauge
for ordinary
and
thin
double-lugalloy
(three-quarter
hard-H6).
fixed
anchor nuts
(see Table 8)
27
L 163,
forgauge
sheetfor
and
strip of aluminium-coated
Table

16Specification
— Acceptance
attachment
plates for ordinary
aluminium-copper-magnesium-silicon-manganese
alloy (solution treated, cold
and
thin double-lug floating anchor nuts (see Table 10)
28
worked
forAcceptance
flattening and
aged
room temperature)
Table
17 —
gauge
forat
ordinary
and thin nut and baseplate
(Cu 4.4, Mg 0.5,
0.8, Mn 0.8).
subassemblies
for Si
double-lug
floating anchor nuts
L 168,
Specification
for bars(see
andTable

extruded
(see
Table
10) and stripnuts
12) sections of
29
aluminium-copper-magnesium-silicon-manganese
alloy
(solution
treated
and
Table 18 — Acceptance gauge for ordinary and thin single-lug
artificially
(notTable
exceeding
fixed
anchor aged)
nuts (see
11) 200 mm diameter or minor sectional
30
dimension).
Table 19 — Acceptance gauge for attachment strips for ordinary
S 80,
Specification
forTable
high chromium-nickel
corrosion-resisting steel billets,31
and
thin
stripnuts (see

12)
bars, forgings and parts (880–1 080 MPa; limiting ruling section 100 mm).
S 92, Carbon-manganese steel (suitable for welding).
S 95, 11/2 per cent nickel-chromium-molybdenum steel.
S 112, Semi-free cutting carbon steel, bright bars for machining (primarily
intended for the manufacture of nuts).
S 113, “40” carbon steel bright bars for machining (primarily intended for the
manufacture of nuts).
S 114, Manganese-molybeenum steel.
S 117, 1 per cent chromium steel.
S 137, Specification for high chromium-nickel corrosion-resisting steel bright
bars (free machining) (880–1 080 MPa; limiting ruling section 70 mm).
S 154, 21/2 per cent nickel-chromium-molybdenum steel billets, bars, forgings
and parts (880–1 080 MPa: limiting ruling section 150 mm).
S 510, Carbon steel sheet and strip (430–540 MN/m2) (suitable for welding).
S 511, Deep drawing carbon steel sheet and strip (280–400 MN/m2) (suitable
for welding).
S 526, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(titanium stabilized: 54 hbar).
S 527, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(niobium stabilized: 54 hbar).
b) Ministry of Defence specifications
AD 114, Design requirements, qualification approval tests and acceptance test
for AGS 2000 series stiffnuts (BA and BSF threads)2).
DEF 151, Anodizing of aluminium and aluminium alloys.
DEF 2331, Protective PX-1, dyed and undyed.
DEF STAN, 03-8 Electro-deposition of tin.
2)

iv

ii

Referred to in foreword only.
© BSI
BSI 2010
2010
©
© The British Standards Institution
2013


John Devaney, British Licensed
StandardsCopy:
Institution,
Mr. John
27/07/2012
Devaney,
10:58,
British
Uncontrolled
Standards Institution,
Copy, (c) The
27/07/2012
British Standards
10:58, Uncontrolled
Institution 2012
Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,

193,3A
3A213
201,
to 2A 216:1981
3A200,
3A201,
200,2A
3A 193, 3A
to2A
2A213
216:1981+A1:2013

Foreword
DEF STAN, 03-9 Electro-deposition of silver.
This
British
Standard
is
published
BSI
Standards
licence
Self-retaining
nuts
were
first
introduced
toand
the strips.
BritishLimited,

aircraft under
industry
during
DTD
10, High
nickel
copper
alloy by
sheets
from1930’s.
The British
Standards
the
They were
widelyInstitution.
adopted and soon constituted a large proportion of
DTD
417,
Lubricating
oil, aircraft controls: anti-freezing.
the
nuts
used
in aircraft
BS 3A
125
to 3A
132, 3A construction.
136 to 3A 143, 3A 147 to 3A 168, 3A 180, 3A 181, 3A
DTD

904,
186,
3A
187, Cadmium
3A 192,
3Aplating.
193,
200,were
3A 201,
2A 213
216:1981+A1:2013
Being
proprietary
articles,
the3A
nuts
required
by to
the2Aairworthiness
3)168, 3A 180,
c) SocietyBS
British
Companies
(SBAC)
publication
supersedes
3A 125 Aerospace
to
3Aand
132,approval

3A 136 to
143,
3A
147 to 3A
authorities
toofundergo
test
by3A
the
Royal
Aircraft
Establishment,
1)
3ARS
181,
3A
186,
3A
187,
3A
192,
3A
193,
3A
200,
3A
201,
2A
213
2A 216:1981,

,
AD
114,
setting
out the
Farnborough,
who
in
1942
published
a
specification
732, Manufacturers identification monograms for aerospacetofasteners.
which is
withdrawn.
design
and
test requirements.
The
term
“stiffnut”
was
chosen
as 143,
the most
suitable
BS
3A
125
to

3A
132,
3A
136
to
3A
3A
147
This publication does not purport to include all the necessary provisions of
a to
descriptive
name
for
generic
use.
Text introduced
or altered
by Amendment
No.181,
1 is indicated
the187,
text by
3A 168,
3A
180,
3A
3A 186,in3A
3Atags
192,
contract.

Users are
responsible
for its
correct
application.
.
Minor editorial
changes
are
not
tagged.
The
specification
AD 114
was
the
first
step
towards
stiffnuts,
3A
193,
3A
200,
3A
201,standardization
2A 213 to 2Aof216:1981
Compliance
with a general
Britishrequirements

Standard does
conferperformance
immunity
and
specified certain
andcannot
the minimum
CAUTION.
BS A 125, A 126, A 127, A 128, A 136, A 137, A 138, A 139, A 147,
from
legalin
obligations.
acceptable
respect of retaining properties. Manufacture, however, was to
A 148, A 149, A 150, A 151, A 152, A 157, A 158,A 159, A 160, A 165, A 166,
proprietary
approved
the RAEasand
nuts were
knownwhich
to users
their
A 213 and Adrawings
215 stiffnuts
haveby
cadmium
a plating
material
hasby
been

proprietary
names
and
part
numbers.
This
continued
until
1947,
when
drawings
restricted and / or banned for use in many countries owing to environmental and
were
issued
in theThey
Society
of British
Companies
Limited
AGSofficials
series
health
concerns.
should
not be Aerospace
used in new
product designs.
Local
providing
common

part
numbers
to
which
nuts
of
any
make
could
be
supplied;
should be consulted about any concerns on using cadmium plated parts.
maximum envelope dimensions were specified and also other features affecting
Self-retaining nuts from
werethe
firstuser’s
introduced
the British
industry
interchangeability
point oftoview,
but theaircraft
nuts were
still during
the
1930’s.
They
were
widely
adopted

and
soon
constituted
a
large
proportion
of
manufactured and inspected to the makers’ drawings. At a later date, too,
the nuts usedtesting
in aircraft
construction.
performance
of production
quantities was introduced to ensure that the
frictional
properties
were maintained
at or
above the
of AD 114, which
Being proprietary
articles,
the nuts were
required
by standard
the airworthiness
had
covered
only
the

type
testing
of
prototype
nuts
when
submitted
for approval.
authorities to undergo test and approval by the Royal Aircraft Establishment,
1)
,
AD
114,
setting
outBritish
the
Farnborough,
who
in
1942
published
a
specification
With the opportunity afforded by the advent of the Unified screw thread,
design
and
test
requirements.
The
term

“stiffnut”
was
chosen
as
the
most
suitable
Standards A 125 to A 168 were published in 1954 to fulfil the functions
descriptive
name for generic
use. the AGS drawings, production test schedules
previously performed
by AD 114,
and,
to
a
large
extent,
the
manufacturers’
The AGS drawings
were
The specification AD 114 was the first stepdrawings.
towards standardization
of stiffnuts,
devised
around
a
number
of

existing
products
and
could
not,
therefore,
supply
a
and specified certain general requirements and the minimum performance
precise
definition,
but
it
has
been
possible
in
the
new
series
of
nuts
to
coordinate
acceptable in respect of retaining properties. Manufacture, however, was to
developmentdrawings
with theapproved
preparation
of the
British

Standards,
resulting
in by
a much
proprietary
by the
RAE
and nuts
were known
to users
their
fuller specification.
Thepart
aim numbers.
throughout
hascontinued
been to define
and dimension
the
proprietary
names and
This
until 1947,
when drawings
product
completely
so thatof
the
standards
are adequate

for manufacture
were
issued
in the Society
British
Aerospace
Companies
Limited AGSand
series
inspection,common
except for
the
friction to
element,
which
defined
the be
space
it may
providing
part
numbers
which nuts
ofisany
makeby
could
supplied;
occupy andenvelope
the performance
which

it has
to attain.
Stiffnuts
these
maximum
dimensions
were
specified
and also
othersupplied
featuresto
affecting
British
Standards will
bepoint
interchangeable,
onenuts
makewere
withstill
another,
interchangeability
fromtherefore
the user’s
of view, but the
within
the specified
limiting conditions
(e.g. drawings.
of temperature,
etc.).date, too,

manufactured
and inspected
to the makers’
At a later
performance
of production
quantities up
wastointroduced
to ensure
that the
This revision testing
brings these
British Standards
date, notably
with regard
to
frictional
properties
were maintained
at and
or above
the standard
of ADstandards.
114, which
the qualification
approval
requirements
the references
to other
had

the typethe
testing
of prototype
nuts whenin
submitted
for approval.
Thiscovered
revisiononly
supersedes
previous
edition published
1958, which
is
With
the opportunity
therefore
withdrawn. afforded by the advent of the Unified screw thread, British
Standards
A 125 make
to A 168
were published
in 1954
to of
fulfil
functions
These standards
reference
to the latest
issues
thethe

following.
previously performed by AD 114, the AGS drawings, production test schedules
a) to
British
Standards
and,
a large
extent, the manufacturers’ drawings. The AGS drawings were
BS 919,
Screwa gauge
limits
and tolerances
Part
1: Gauges
for screwsupply
threads
devised
around
number
of existing
products—and
could
not, therefore,
a
of Unified
form.but it has been possible in the new series of nuts to coordinate
precise
definition,
1
development

with the
preparation
of the
British
/4 in andin a much
BS 1580, Unified
screw
threads —
Parts
1 & 2:Standards,
Diameters resulting
1
fuller
specification.
The
aim
throughout
has
been
to
define
and
dimension the
larger — Part 3: Diameters below /4 in.
Summary
of pagesso that the standards are adequate for manufacture and
product
completely
inspection,
except

for the friction
element,
defined
bypages
the space
it may
This document
comprises
a front cover,
an which
inside is
front
cover,
i to vi,
occupy
the
performance
which it has to attain. Stiffnuts supplied to these
pages 1and
to 31
and
a back cover.
British Standards will therefore be interchangeable, one make with another,
This standard has been updated (see copyright date) and may have had
within the specified limiting conditions (e.g. of temperature, etc.).
amendments incorporated. This will be indicated in the amendment table on the
This
brings these British Standards up to date, notably with regard to
insiderevision
front cover.

the qualification approval requirements and the references to other standards.
This revision supersedes the previous edition published in 1958, which is
therefore
withdrawn.
3) Obtainable from the Society of British Aerospace Companies, 29 King Street, St. James’s,
1)
Now issued by the Ministry of Defence, Assistant Directorate of Standardization (Air).
These
make reference to the latest issues of the following.
London,standards
SW1.
a) British Standards
iii
v
©
© BSI
The 2010
British Standards Institution
BS2013
919, Screw gauge limits and tolerances — Part 1: Gauges for screw threadsiii
of Unified form.
BS 1580, Unified screw threads — Parts 1 & 2: Diameters 1/ in and

Foreword


Licensed
Copy:
Mr.
John

Devaney,
British
Standards
Institution,
27/07/2012
10:58,
Uncontrolled
Copy,
(c)2012
The
British Standards Institution 2012
opy:
:Copy:
Mr.Mr.
John
Mr.
John
Devaney,
John
Devaney,
Devaney,
British
British
British
Standards
Standards
Standards
Institution,
Institution,
Institution,

27/07/2012
27/07/2012
27/07/2012
10:58,
10:58,
10:58,
Uncontrolled
Uncontrolled
Uncontrolled
Copy,
Copy,
Copy,
(c) (c)
The
(c)
The
British
The
British
British
Standards
Standards
Standards
Institution
Institution
Institution
2012
2012

precise definition, but it has been possible in the new series of nuts to coordinate

development with the preparation of the British Standards, resulting in a much
BS 3A 125 to 3A 132,fuller
3A 136
to 3A 143,
3A throughout
147 to has been to define and dimension the
specification.
The aim
product
so that
standards are adequate for manufacture and
3A 168, 3A 180, 3A 181,
3A completely
186, 3A 187,
3Athe192,
inspection,
except
for 216:1981
the friction element, which is defined by the space it may
3A 193, 3A 200, 3A 201,
2A 213
to 2A
216:1981+A1:2013
occupy and the performance which it has to attain. Stiffnuts supplied to these
British Standards will therefore be interchangeable, one make with another,
within the specified limiting conditions (e.g. of temperature, etc.).
This revision brings these British Standards up to date, notably with regard to
the qualification approval requirements and the references to other standards.
BS 2870, Rolled copper and copper alloys. Sheet, strip and foil.
This revision supersedes the previous edition published in 1958, which is

BS 2874,withdrawn.
Copper and copper alloys. Rods and sections (other than forging
therefore
stock).
These standards make reference to the latest issues of the following.
3488,
anhydrous
lanolin.
BS 3A 125 to 3A 132,BS
3A
136Technical
to
3A 143,
3A 147
to
a) British
Standards
A3A
102,
Steel
bolts
(Unified
and Unified threads) for aircraft.
BS
3A 125
3A3A
132,
136
to
3A

143,
3A
147
totolerances
3A 168,
3A to
180,
181,
186,
3A
187,limits
3Ahexagons
192,
BS3A
919-1:
Screw
gauge
limits
and
Part1:1:Gauges
Specification
forthreads
gauges
919,
Screw
gauge
and
tolerances
—–Part
for screw

A
104,
Corrosion-resisting
steel
bolts
(Unified
hexagons
and
Unified
threads)
3A
168,
3A
180,
3A
181,
3A
186,
187,
192,
BS
3A
125
to
3A
132,
3A
136
to
3A

143,
3A
147
to
for
screw
threads
of
unified
form
of
Unified
form.
3A 193, 3A 200, 3A 201, 2A 213 to 2A 216:1981
for aircraft.
1 diameters ¼ in
3A 193,
201,
2A
213
to
216:1981
168, 3A 200,
180, 3A 181,
186,
3A2A
187,
3A
192,—Part
BS3A

1580-1:
Unified
screw
threads
1: 1Screw
threads with
/4 in and
1580,
Unified
screw
threads
Parts
& 2: Diameters
1
A
169,
Aluminium
alloy
bolts
(Unified
hexagons
and
Unified
threads) for
and
larger
larger
Part
Diameters
below /4 in.

3A 193, 3A 200, 3A 201,
2A —
213
to3:2A
216:1981
aircraft.
BS 1580-3: Unified screw threads - Part 3: Screw threads with diameters
Bbelow
11, Brass
suitable to be brazed or silver soldered.
¼ in bars
– Requirements
1/ per cent magnesium alloy (soft-0).
LBS
80,2870,
SheetRolled
and strip
of aluminium-2
4
copper
and copper alloys.
Sheet, strip and foil.

© BSI 2010

iv

1
LBS
81,2870,

SheetRolled
and strip
aluminium-2
/4 perand
centsections
magnesium
alloy
copper
and copper
Sheet,
strip and
foil.
BS
2874,
Copper
andofcopper
alloys.alloys.
Rods
(other
than forging
(three-quarter
hard-H6).
2870, Copper
Rolled copper
and copper
Sheet,
strip and
foil.
stock).
BS

2874,
and copper
alloys.alloys.
Rods and
sections
(other
than forging
Lstock).
163,
Specification
for
sheet and
strip
of aluminium-coated
BS
2874,
Copper
and
copper
alloys.
Rods
and sections (other than forging
3488,
Technical
anhydrous
lanolin.
aluminium-copper-magnesium-silicon-manganese
alloy (solution treated, cold
stock).
BS

3488,
Technical
anhydrous
lanolin.
A
Steel
bolts
(Unified
hexagons
andwith
Unified
threads)
for aircraft.
BS102,
EN
2133:
Cadmium
plating
of steels
specified
tensile
strength
worked
for
flattening
and
aged
at
room
temperature)

≤
1450
MPa,
copper,
copper
alloys
and
nickel
alloys
BS
3488,
Technical
anhydrous
lanolin.
A
102,
Steel
bolts
(Unified
hexagons
and
Unified
threads)
for
aircraft.
A 104,
steelAssistant
bolts (Unified
hexagons and Unified threads)
1) (Cu

4.4, Corrosion-resisting
Mg
0.5,Ministry
Si 0.8,ofMn
0.8).
Now issued
by the
Defence,
Directorate of Standardization (Air).
102,
Steel bolts (Unified steel
hexagons
Unified
threads)
forUnified
aircraft.
for104,
aircraft.
A
Corrosion-resisting
boltsand
(Unified
hexagons
and
threads)
L 168, Specification for bars and extruded sections of
for
aircraft.
A 104,
steel

bolts (Unified
hexagons
and Unified
threads)
169, Corrosion-resisting
Aluminium alloy bolts
(Unified
hexagons
and
Unified
threads)
for
aluminium-copper-magnesium-silicon-manganese
alloy
(solution
treated
and
iii
for
aircraft.
aircraft.
A
169,
Aluminium
alloy
bolts
(Unified
hexagons
and
Unified

threads)
artificially aged) (not exceeding 200 mm diameter or minor sectional for
aircraft.
A
Aluminium
alloy bolts
hexagons
and Unified threads) for
B 169,
11, Brass
bars suitable
to be(Unified
brazed or
silver soldered.
dimension).
aircraft.
11,Specification
Brass and
barsstrip
suitable
tochromium-nickel
be brazed1/or
silver
soldered.
per
cent
magnesium
alloy
(soft-0).
L80,

80,
Sheet
aluminium-2
SB
for of
high
corrosion-resisting
steel
billets,
4
1/orper
B
11,
Brass
bars
suitable
to
be
brazed
soldered.
L
80,
Sheet
and
strip
of
aluminium-2
cent
magnesium
alloy

(soft-0).
bars,
forgings
and
parts
(880–1
080
MPa;
limiting
ruling
section
100
mm).
1 4 silver
L 81, Sheet and strip of aluminium-2 /4 per cent magnesium alloy
80,Carbon-manganese
SL
92,
steel (suitable1/4for
81,
Sheet and
strip of aluminium-2
perwelding).
cent magnesium alloy (soft-0).
(three-quarter
hard-H6).
1
1
(three-quarter
hard-H6).

L
81,
Sheet
and
strip
of
aluminium-2
/
per
cent steel.
magnesium alloy
S 95,
1 /Specification
163,
for sheet and strip4of aluminium-coated
2 per cent nickel-chromium-molybdenum
(three-quarter
hard-H6).
aluminium-copper-magnesium-silicon-manganese
(solution
treated, cold
163,Semi-free
Specification
for carbon
sheet and
strip
of aluminium-coated
SL
112,
cutting

steel,
bright
bars foralloy
machining
(primarily
worked
for
and
aged
at strip
room of
temperature)
aluminium-copper-magnesium-silicon-manganese
alloy (solution treated, cold
L 163, Specification
for
sheet
and
aluminium-coated
intended
forflattening
the manufacture
of
nuts).
(Cu 4.4,for
Mgflattening
0.5, Si 0.8,
Mnaged
0.8).at room temperature)
worked

and
alloy (solution
treated,
cold
Saluminium-copper-magnesium-silicon-manganese
113, “40” carbon steel bright bars for machining (primarily
intended
for the
(Cu
4.4,
Mg
0.5,
Si
0.8,
Mn
0.8).
worked
for
flattening
and
aged
at
room
temperature)
L
168,
Specification
for
bars
and

extruded
sections
of
manufacture of nuts).
(Cu
4.4,Specification
Mg 0.5, Si 0.8,
aluminium-copper-magnesium-silicon-manganese
L
168,
for Mn
bars0.8).
and extruded sections alloy
of (solution treated and
S 114, Manganese-molybeenum steel.
artificially
aged) (notfor
exceeding
mm diameter
sectional
aluminium-copper-magnesium-silicon-manganese
alloy
(solution
treated and
L
168, Specification
bars and200
extruded
sectionsor
ofminor

Sartificially
117, 1 per aged)
cent chromium
steel.200 mm diameter or
dimension).
(not exceeding
minor
sectional
aluminium-copper-magnesium-silicon-manganese
alloy
(solution
treated and
Sdimension).
Specification
forexceeding
high chromium-nickel
chromium-nickel
corrosion-resisting
steel billets,
bright
artificially
aged) (not
200 mm diameter
or minor sectional
S137,
80, Specification
for
high
corrosion-resisting
steel

bars
machining)
080080
MPa;
limiting
ruling
section
70 steel
mm).
dimension).
bars,
forgings
and parts
(880–1
MPa;
limiting
ruling
section
100 mm).
S
80,(free
Specification
for(880–1
high
chromium-nickel
corrosion-resisting
billets,
andnickel-chromium-molybdenum
parts
(880–1

080 MPa;
ruling
section
100
mm).
steel
billets,
bars,
forgings
Sbars,
21/2 per cent
S154,
80,
Specification
for high
chromium-nickel
corrosion-resisting
steel
billets,
92, forgings
Carbon-manganese
steel
(suitable
forlimiting
welding).
and
parts
(880–1
080
MPa:

limiting
ruling
section
150
mm).
bars,
forgings
and
parts
(880–1
080
MPa;
limiting
ruling
section
100
mm).
S
92,
Carbon-manganese
steel
(suitable
for
welding).
1
S 95, 1 /2 per cent nickel-chromium-molybdenum steel.
2) (suitable for welding).
1/ per cent
SS510,
Carbon

steelnickel-chromium-molybdenum
sheet and
(430–540
MN/m
92,
Carbon-manganese
steelstrip
(suitable
for welding).
2
S 95,
112,1
Semi-free
cutting carbon
steel, bright
bars steel.
for machining (primarily
2) (suitable
1/ per
SS
511,
drawing
carbon
steel
sheetbright
and strip
MN/m(primarily
centmanufacture
nickel-chromium-molybdenum
steel.

95,
intended
of steel,
nuts).
112,1Deep
Semi-free
cutting
carbon
bars(280–400
for machining
2 for the
for
welding).
intended
forcarbon
the manufacture
ofbars
nuts).
S 112,
cutting
carbon
steel,
bars for
machining
(primarily
113, Semi-free
“40”
steel bright
forbright
machining

(primarily
intended
for the
SS
526,
Softened
18/10
chromium-nickel
steelintended
sheet andfor
strip
intended
forcarbon
the
manufacture
nuts).
manufacture
of nuts).
113, “40”
steel brightofbars
forcorrosion-resisting
machining (primarily
the
(titanium
stabilized:
54
hbar).
manufacture
of nuts).
S 113,

carbon
steel bright bars
for machining (primarily intended for the
114, “40”
Manganese-molybeenum
steel.
SS
527, Softened
chromium-nickel corrosion-resisting steel sheet and strip
manufacture
of18/10
nuts).
S 114,
117, Manganese-molybeenum
1 per cent
chromium steel.steel.
(niobium
stabilized:
54
hbar).
114,
Manganese-molybeenum
steel.
S
per cent chromium
S 117,
137, 1
Specification
for highsteel.
chromium-nickel

corrosion-resisting steel bright
b)S Ministry
of
Defence
specifications
117,
1
per
cent
chromium
steel.
bars
(free
machining)
080 MPa; limiting
ruling section 70 steel
mm).bright
137,
Specification
for(880–1
high chromium-nickel
corrosion-resisting
AD
114,
Design
requirements,
qualification
approval
tests
and acceptance

test
bars
(free
080
MPa; limiting
ruling
section
70
mm).
1 machining)
137,
Specification
for(880–1
high chromium-nickel
corrosion-resisting
steel
bright
/2 per cent nickel-chromium-molybdenum
steel
billets,
bars,
forgings
S 154,
2
2).
for
AGS
2000
series
stiffnuts

(BA
and
BSF
threads)
1
bars
(free
(880–1limiting
080 MPa;
limiting
ruling
section
mm).
per cent080
nickel-chromium-molybdenum
steel
billets, 70
bars,
forgings
S
154,
2 /2machining)
and
parts
(880–1
MPa:
ruling
section
150 mm).
DEF

151,
ofMPa:
aluminium
and
aluminium
alloys.
1 Anodizing
2
and
parts
(880–1
080
limiting
ruling
section
150
mm).
billets, for
bars,
forgings
154, Carbon
2 /2 per cent
) (suitable
welding).
S 510,
steelnickel-chromium-molybdenum
sheet and strip (430–540 MN/msteel
DEF
2331,
Protective

PX-1,
dyed
and(430–540
undyed.
2) (suitable
and
parts
(880–1
080
MPa:
limiting
ruling
section
150
mm).
2
for
welding).
S
510,
Carbon
steel
sheet
and
strip
MN/m
S 511, Deep drawing carbon steel sheet and strip (280–400 MN/m ) (suitable
DEF
STAN,
Electro-deposition

of tin.
2) (suitable for2 welding).
S 510,
Carbon
steel
sheet
andsteel
stripsheet
(430–540
MN/m
for
welding).
511,
Deep 03-8
drawing
carbon
and strip
(280–400
MN/m ) (suitable
2) (suitable
for
welding).
511, Softened
Deep drawing
steel sheet corrosion-resisting
and strip (280–400 steel
MN/m
S 526,
18/10 carbon
chromium-nickel

sheet
and strip
for
welding).
(titanium
stabilized:
54
hbar).
S
526,
Softened
18/10
chromium-nickel
corrosion-resisting
steel
sheet
and strip
2)
Referred to in foreword only.
(titanium
stabilized:
54
hbar).
526, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
S 527,
(titanium
stabilized:
54
hbar).
(niobium

stabilized:
hbar).
S 527, Softened
18/1054
chromium-nickel
corrosion-resisting steel sheet ©
and
BSIstrip
2010
© The British Standards Institution
2013
(niobium
stabilized:
54
hbar).
S 527,
Softened
18/10 chromium-nickel
corrosion-resisting steel sheet and strip
b)
Ministry
of Defence
specifications
(niobium
stabilized:
54specifications
hbar). qualification approval tests and acceptance test
b)
of Defence
ADMinistry

114, Design
requirements,


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c)
The British
Licensed
Copy:Standards
Mr. John Institution
Devaney, 2012
British Standards Instit

ohn
d
r. Copy:
John
Devaney,
Devaney,
Mr. John
British
British
Devaney,
Standards
Licensed
Licensed
Standards
British
Copy:
Institution,
Copy:

Standards
Institution,
Mr.
Mr. John
John
27/07/2012
Institution,
27/07/2012
Devaney,
Devaney,
10:58,
27/07/2012
British
British
10:58,
Uncontrolled
Standards
Standards
Uncontrolled
10:58,Copy,
Institution,
Uncontrolled
Institution,
Copy,
(c) The
(c)
27/07/2012
27/07/2012
The
Copy,

British
British
(c)
Standards
10:58,
The
10:58,
Standards
British
Uncontrolled
Uncontrolled
Institution
Standards
Institution
2012
Copy,
Copy,
Institution
2012(c)
(c) The
The
2012
British
British Standards
Standards Institution
Institution 2012
2012

S 113,
“40”

steel3A
bright
BS 3A 125 to 3A 132, 3A
136
tocarbon
3A 143,
147bars
to for machining (primarily intended for the
manufacture of nuts).
3A 168, 3A 180, 3A 181, 3A 186, 3ABS
187,
192,
BS
3A3A
125
tosteel.
3A 132,
132, 3A
3A 136
136 to
to 3A
3A 143,
143, 3A
3A 147
147 to
to
3A
125
to
3A

S 114, Manganese-molybeenum
3A 193, 3A 200, 3A 201, 2A 213 to 2A3A
216:1981
3A
168,
3A
180,
3A
181,
3A
186,
3A
187,
3A
192,
168, steel.
3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
S 117, 1 per cent chromium
193,
3A213
201,
to 2Asteel
216:1981
3A
3A201,
200,2A
3A
193,
3A
200,

3A
to2A
2A213
216:1981+A1:2013
S 137, Specification for high chromium-nickel
corrosion-resisting
bright
bars (free machining) (880–1 080 MPa; limiting ruling section 70 mm).

iv

S 154, 21/2 per cent nickel-chromium-molybdenum steel billets, bars, forgings
and parts (880–1 080 MPa: limiting ruling section 150 mm).
BS 2870, Rolled copper and copper alloys. Sheet, strip and foil.
S 510, Carbon steel sheet and strip (430–540 MN/m2) (suitable for welding).
BS 2874, Copper and copper alloys. Rods and sections (other than forging
S 511,
Deep drawing
carbon steel sheet
and strip (280–400 MN/m2) (suitable
stock).
DEF
STAN,
03-9 Electro-deposition
of silver.
DEF
STAN,
03-9
Electro-deposition of
silver.

for welding).
BS 3488,
Technical
lanolin.
DTD
10, High
High
nickelanhydrous
copper alloy
alloy
sheets and
and strips.
strips.
DTD
10,
nickel
copper
sheets
S 526, Softened BS
18/10
chromium-nickel
corrosion-resisting
steel sheet
strip
3A
125
to
3A
132,
3A

136
to 3A
3Aand
147
to
A
102,
Steel
bolts
(Unified
hexagons
and
Unified
threads)
for143,
aircraft.
DTD
417,
Lubricating
oil,
aircraft
controls:
anti-freezing.
DTD
417, Lubricating
aircraft controls: anti-freezing.
(titanium
stabilized: 54oil,
hbar).
3A

168,
3A
180,
3A
181,
3A
186,
3A
187,
3A
192,
A 104,904,
Corrosion-resisting
steel bolts (Unified hexagons and Unified threads)
DTD
Cadmium
DTD
Cadmium
plating.
S 527,904,
Softened
18/10plating.
chromium-nickel corrosion-resisting steel sheet and strip
for
aircraft.
3A
193,
200, 3A
201, publication
2A 213 to3)

3)2A 216:1981
c)
Society stabilized:
of British
British Aerospace
Companies
(SBAC)
publication
(niobium
54 hbar). 3A
c)
Society
of
Aerospace
Companies
(SBAC)
A
169,
Aluminium
alloy
bolts
(Unified
hexagons
and
Unified
threads)
RS
732, Manufacturers
identification
monograms

forto
aerospace
fasteners.
BS 3Aspecifications
125 to 3A 132,
3A 136
3A 143,
3A for
147 to
b) Ministry
of Defence
RS
732,
Manufacturers
identification
monograms
for
aerospace
fasteners.
aircraft.
3A
3A
3Aall
181,
3A
186,
3A
187,
This
publication

does
not
purport
to180,
include
all
the136
necessary
provisions
of
a192,
ADpublication
114, Design
requirements,
qualification
approval
tests
and
acceptance
test
This
does
not
purport
to
include
the
necessary
provisions
of

a
BS
3A168,
125
to
3A
132,
3A
to
3A
143,
3A3A
147
to
B 11,
Brass
bars
suitable
to be
brazed
or silver
soldered.
2).
contract.
Users
responsible
for
its
correct
application.

for AGS
2000are
series
stiffnuts
(BA
and
BSF
threads)
contract.
Users
are
responsible
for
its
correct
application.
3A
193,
3A
200,
3A
201,
2A
213
to
2A
216:1981
3A
168,
3A

180,
3A
181,
3A
186,
3A
187,
3A
192,
1
L 80, Sheet and strip of aluminium-2 /4 per cent magnesium alloy (soft-0).
DEF
151,Specification
Anodizing
of for
aluminium
anddoes
aluminium
alloys.
BS
1872:
electroplated
coatings
of2A
tin
3A
193,
3A 200,
3A 201,
213 to

2A 216:1981
Compliance
with a
a British
British
Standard
cannot
confer
immunity
Compliance
Standard
cannot
confer
immunity
1 does
L 81, Sheet with
and strip
of aluminium-2
/4 per cent
magnesium
alloy
DEF
2331,
Protective
PX-1,
dyed
and
undyed.
from
legal

obligations.
from
legal
obligations.
DEF
STAN,
03-9
Electro-deposition
of
silver.
(three-quarter hard-H6).
DEFStan
STAN,
03-8
Electro-deposition
of tin.
DTD
High
nickel
copper
alloy
strips.Soft Film, Cold Application
Def
80-217:
Corrosion
L
163,10,
Specification
for
sheetPreventive

and sheets
strip Compound:
ofand
aluminium-coated
DTD
417,03-19:
Lubricating
oil, aircraft controls:
anti-freezing.
aluminium-copper-magnesium-silicon-manganese
alloy (solution treated, cold
Def Stan
Electro-Deposition
of Cadmium
worked
for
flattening
and
aged
at
room
temperature)
2) DTD
904,
Cadmium
plating.
Def-Stan
Acid Anodizing
of Aluminium and Aluminium Alloys
Referred

to in03-25:
foreword
only.
DEF
STAN,
03-9Sulfuric
Electro-deposition
of silver.
(Cu 4.4, Mg 0.5, Si 0.8, Mn 0.8).
c)
Society
of
British
Aerospace
Companies
(SBAC)
publication
10:
Nickel-Copper
Alloy
Cold
Rolled
and
Annealed
Sheet3)and Strip
DTD
10,
High
nickel
copper

alloy
sheets
and
strips.
DEF
03-9 Electro-deposition
of silver.
L 168,STAN,
Specification
for bars and extruded
sections of
© BSI 2010
RS
732,
Manufacturers
identification
monograms
for
aerospace
DTD
417,
Lubricating
oil, aircraft
controls:
DTD
10, High
nickel copper
alloy sheets
andanti-freezing.
strips.alloy (solutionfasteners.

aluminium-copper-magnesium-silicon-manganese
treated and
3)
This
publication
does
not
purport
to
include
allanti-freezing.
the necessary
provisions of a
DTD
904,
Cadmium
plating.
artificially
aged)
(not
exceeding
200
mm diameter
or minor sectional
c) ADS
Group
Limited
(ADS)
publications
DTD

417,
Lubricating
oil,
aircraft
controls:
contract.
Users
are
responsible
for
its
correct
application.
dimension).
3)
c)
Society
British
Aerospace
Companies Monogram
(SBAC) publication
ADS
RS732
Manufacturers
for Aerospace
Fasteners
DTD
904, of
Cadmium
plating.Identification

S
80,
Specification
for
high
chromium-nickel
corrosion-resisting
steel billets,
Compliance
a British
Standard
does
cannot
confer
immunity
RS
732,QUALIFIED
Manufacturers
identification
monograms
for
aerospace
TS200
MANUFACTURERS
FOR
ADS
AEROSPACE
3) fasteners.
c)
Society

ofwith
British
Aerospace
Companies
(SBAC)
publication
bars,
forgings
and parts (880–1
080 MPa;
limiting
ruling
section 100 mm).
from
legal
obligations.
INDUSTRY
STANDARD
PARTS
AGS,
ESC
SERIES)
This
publication
does not purport
to (AS,
include
allAND
the necessary
provisions

of a
RS
732, Manufacturers
identification
monograms
for
aerospace
fasteners.
S 92, Carbon-manganese
steelfor
(suitable
for welding).
contract.
Users are responsible
its correct
application.
This publication
does not purport to include all the necessary provisions of a
1/ per cent nickel-chromium-molybdenum steel.
S 95, 1Users
2
contract.
are a
responsible
for its correct
Compliance
with
British Standard
doesapplication.
cannot confer immunity

S 112,
Semi-free
cutting carbon steel, bright bars for machining (primarily
from
legal
obligations.
Compliance
a British Standard
does cannot
confer
immunity
confer
immunity
from
intended forwith
the manufacture
of nuts). cannot
legal
from obligations.
legal obligations.
S 113, “40” carbon steel bright bars for machining (primarily intended for the
manufacture of nuts).
S 114, Manganese-molybeenum steel.
S 117, 1 per cent chromium steel.
S 137, Specification for high chromium-nickel corrosion-resisting steel bright
bars (free machining) (880–1 080 MPa; limiting ruling section 70 mm).
S 154, 21/2 per cent nickel-chromium-molybdenum steel billets, bars, forgings
and parts (880–1 080 MPa: limiting ruling section 150 mm).
S 510, Carbon steel sheet and strip (430–540 MN/m2) (suitable for welding).
S 511, Deep drawing carbon steel sheet and strip (280–400 MN/m2) (suitable

for welding).
S 526, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(titanium stabilized: 54 hbar).
S 527, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(niobium stabilized: 54 hbar).
b) Ministry of Defence specifications
Summary
of
Summary
of pages
pages
AD 114, Design
requirements, qualification approval tests and acceptance test
This
document
a
cover,
inside
front
pages
This
comprises
a front
front(BA
cover,
an
inside
front2)cover,
cover,
pages ii to

to vi,
vi,
.
fordocument
AGS 2000comprises
series stiffnuts
andan
BSF
threads)
pages
1
to
31
and
a
back
cover.
pages
1
to
31
and
a
back
cover.
DEF 151, Anodizing of aluminium and aluminium alloys.
This
standard
has
(see

copyright
date) and may have had
This
standard
has been
been updated
updated
(seeand
copyright
DEF
2331, Protective
PX-1, dyed
undyed.date) and may have had
amendments
amendments incorporated.
incorporated. This
This will
will be
be indicated
indicated in
in the
the amendment
amendment table
table on
on the
the
DEFfront
STAN,
03-8 Electro-deposition of tin.
inside

cover.
inside front cover.
2)

Referred to in foreword only.
from
the
Society
of website
British Aerospace
Companies,
29 King
King Street,
Street, St.
James’s,
the Society
of
British
Aerospace
Companies, 29
St. James’s,
TS200 only from
is obtainable
from
www.adsgroup.org.uk
London,
London, SW1.
SW1.
© BSI 2010

3)
3) Obtainable
Obtainable

iv

Summary of pages
This document comprises a front cover, an inside front cover, pages i to vi,
pages 1 to 31 and a back cover.

2010
©
BSI
©
© BSI
The 2010
British Standards Institution 2013

v

v
v


vi

blank

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A200,
193,3A
3A201,
200,2A
3A213
201,
to 2A 216:1981
3A 193, 3A
to2A
2A213
216:1981+A1:2013

2.3
Section 1. General requirements
DEF STAN, 03-9 Electro-deposition of silver.

batch
DTD 10, High nickel copper alloy sheets and strips.
the output of an effectively continuous production
DTD 417, Lubricating oil, aircraft
controls:
anti-freezing.
run of each
size of
nut, free from any changes such

1.1 These British Standards cover the dimensions,
904, Cadmium
plating.
as might be expected to result in an appreciable
material, finish, testing andDTD
identification
of
in the(SBAC)
qualitypublication
of the finished
aircraft stiffnuts with Unified
threads.
to variation
3) product
c) Society
ofAccording
British Aerospace
Companies
(See
section
2.)
the materials used in their RS
construction,
the
732, Manufacturers identification monograms for aerospace fasteners.
stiffnuts are classified as satisfactory for use at
2.4
This
publication
does not purport to include all the necessary provisions of a

sustained temperatures within the following
bolt
contract. Users are responsible for its correct application.
ranges:
unless otherwise stated, the term “bolt” includes
a) p 75 C to + 425 C:Compliance
corrosion-resisting
with asteel
Britishany
Standard
cannot
immunity
screweddoes
bolt or
stud ofconfer
the same
material, screw
nuts, silver plated or unplated
from legal obligations.
thread and finish as the standard bolt specified in
clause 14
b) p 75 C to + 200 C: steel and
corrosion-resisting steel nuts, cadmium plated
2.5
c) p 75 C to + 125 C: aluminium alloy, brass or bolt tolerance test
bronze nuts.
a test to measure the torque required to remove a

1 Scope

NOTE All nuts are capable of remaining effective for servicing
operations at p 40 C.

1.2 Stiffnuts of the following types are covered by
these British Standards:
a) hexagon nuts: ordinary, thin and cap
b) anchor nuts:
1) double-lug fixed: ordinary, thin and cap
2) double-lug floating: ordinary and thin
3) single-lug fixed: ordinary and thin.
c) stripnuts floating: ordinary and thin.
1.3 In these standards, the nut bodies, whether of
normal hexagon form or not, have a thread strength
as least as great as the corresponding standard
nuts.

2 Definitions
For the purposes of these British Standards the
following definitions apply.
2.1
attachment plate (or cage)
the formed sheet-metal plate of a floating anchor
nut that carries the rivet lugs and retains the nut
body, allowing a specified float in relation to the
structure
2.2
baseplate

stiffnut from a bolt of minimum diameter after the
friction element has been strained by assembly on a

bolt of maximum diameter
2.6
cap nut

a stiffnut whose threaded bore is closed by a metal
cap above the friction element, to prevent leakage of
liquid or gas
2.7
endurance test
a test to measure the torque required to remove a
stiffnut from a standard bolt after a specified
number of applications
2.8
fixed anchor nut
a stiffnut having, at the bearing face and integral
with the nut body, a lug or lugs by which it may be
riveted in position, the nut becoming rigidly located
in relation to the supporting structure
2.9
floating anchor nut
a stiffnut in which the nut body, integral with a
baseplate, is retained in an attachment plate that
has lugs by which it may be riveted in position.
Provision is made for a limited amount of movement
of the nut within the attachment plate to allow
alignment on assembly

the plate, normal to the axis of the nut, that forms
Summary of pages
the rivet lugs of a fixed anchor nut or the flange of a 2.10

friction
This document
comprises
cover,element
an inside front cover, pages i to vi,
floating anchor nut or stripnut
for retaining
the nuta front
pages
1
to
31
and
a
back
cover.
body in the attachment plate. The baseplate is
the portion of a stiffnut, above the nut body,
always integral with the This
nut body
standard has been updated
(see copyright
andbetween
may have
designed
to imposedate)
friction
thehad
stiffnut and
amendments incorporated. This

be indicated
the amendment
table
thewill
screw
thread onin
which
it is mounted.
Theon the
inside front cover.
friction element is contained between the minimum
thread length and the maximum overall height of
the stiffnut, and within the maximum plan form of
the standard nut body
3)
Obtainable from the Society of British Aerospace Companies, 29 King Street, St. James’s,
London, SW1.

© BSI
BSI
2010
©
The 2010
British Standards Institution 2013

v
1


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 193, 3A 200, 3A 201, 2A 213 to 2A 216:1981
216:1981+A1:2013

BS 2870, Rolled copper and2.18
copper alloys. Sheet, strip and foil.
torsional
strength
test (for
anchor
nuts
and
BS 2874, Copper and copper
alloys. Rods
and sections
(other
than
forging
stripnuts)
stock).
the baseplate is said to be integral with the nut body
BS 3488,
Technical
when the two are manufactured
in one
piece or anhydrous
a testlanolin.
to confirm that the anchorage will withstand

when they are joined by welding,
brazing
or
similar
torsion
likely
to bethreads)
applied for
through
the bolt
A 102, Steel bolts (Unified any
hexagons
and
Unified
aircraft.
fusion process
under adverse conditions of assembly
A 104, Corrosion-resisting steel bolts (Unified hexagons and Unified threads)
2.12
for aircraft.
3 Design and dimensions
nut body
A 169, Aluminium alloy bolts (Unified hexagons and Unified threads) for
the portion of a stiffnut containing
the screw thread 3.1 All nuts shall, after coating where applicable,
aircraft.
to the dimensions and tolerances specified
and having wall thickness and
height
to toconform

B 11,
Brasssufficient
bars suitable
be brazed or silver soldered.
in
Table
6 to Table 12.
provide the required strength
L 80, Sheet and strip of aluminium-21/4 per cent magnesium alloy (soft-0).
3.2 The friction elements and certain other features
2.13
L 81, Sheet and strip of aluminium-2
cent magnesium
of the nuts1/are
defined
in Table 6 alloy
to Table 12 by
4 per
random sample
(three-quarter hard-H6). maximum envelope dimensions, and in section 2 by
a sample taken in such a manner that every nut in functional test requirements. For inspection
L 163, Specification for sheet and strip of aluminium-coated
the batch has a substantially equal chance of
purposes the manufacturer
provide
approved
aluminium-copper-magnesium-silicon-manganese
alloyshall
(solution
treated,

cold
selection, so that the sample is thus a representative drawings (see clause 10) of all such features, with
worked for flattening and aged at room temperature)
cross section of the whole batch
dimensions and limits and including
(Cu 4.4, Mg 0.5, Si 0.8, Mnadequate
0.8).
specifications for jointing processes and
2.14
L 168, Specification for bars and extruded sections of
non-metallic locking elements. Any changes in these
stiffnut
aluminium-copper-magnesium-silicon-manganese alloy (solution treated and
features shall be notified to the quality assurance
a nut body surmounted by aartificially
device thataged)
imposes
(not exceeding 200 mm diameter or minor sectional
authority (see clause 10) who may require
friction between the nut anddimension).
the screw thread on
requalification testing before approving the drawing
which it is mounted; the friction
of such a value
S 80, is
Specification
for highchanges.
chromium-nickel corrosion-resisting steel billets,
that the nut may be considered
The (880–1 080 MPa; limiting ruling section 100 mm).

bars,self-retaining.
forgings and parts
friction is independent of the loading on the face of
4 Material
and
manufacture
S 92, Carbon-manganese steel
(suitable for
welding).
the nut
2.11
integral

steel. metal caps, attachment
S 95, 11/2 per cent nickel-chromium-molybdenum
4.1 Nut bodies, baseplates,
platessteel,
and bright
strips shall
be manufactured
from the
S 112, Semi-free cutting carbon
bars for
machining (primarily
appropriate
intended for the manufacture
of nuts). materials specified in Table 4.
a number of nut bodies integral with baseplates in a Materials used in friction elements and in jointing
S 113, for
“40”

carbontosteel
bars for machining (primarily intended for the
continuous strip of formed section
riveting
the bright
processes shall be in accordance with the approved
manufacture
of nuts).
supporting structure. Provision
is made for
a
drawings; they shall not be adversely affected by
limited amount of movement
theManganese-molybeenum
nuts within the contact
S of
114,
steel.
with or immersion in fuels, lubricants or
attachment strip to allow alignment
on
assembly
S 117, 1 per cent chromiumother
steel.fluids used in aircraft (e.g. water, petroleum
oils,
synthetic oils (sebacic
and adipic esters),
2.16
S 137, Specification for high
chromium-nickel

corrosion-resisting
steel bright
silicone
greases,
castor
oil,
mixtures,
thrust test (for anchor nuts)
bars (free machining) (880–1 080 MPa; limiting rulingpropan-2-ol
section 70 mm).
ethanol,
methanol,
ethanediol,
glycerol).
a test to confirm that the anchorage
withstand
S 154, 21/will
2 per cent nickel-chromium-molybdenum steel billets, bars, forgings
Nut bodies
be produced
the thrust likely to be applied
a bolt
under080 MPa:4.2
andbyparts
(880–1
limiting
rulingshall
section
150 mm).by a machining
process; baseplates of anchor

nuts shall either be
adverse conditions of assembly
2) (suitable for welding).
S 510, Carbon steel sheet and
strip (430–540
MN/mpart
machined
as
an
integral
of
the nut body or shall
2.17
2) (suitable
S 511, Deep drawing carbon
sheet and
MN/m
besteel
produced
fromstrip
strip(280–400
or sheet and
joined
by
torque test
for welding).
welding, brazing or other fusion process. The body
a test to measure the torqueSrequired
to remove
and base-plate

of floating anchorsteel
nutssheet
and and
stripnuts
526, Softened
18/10achromium-nickel
corrosion-resisting
strip
stiffnut from a standard bolt
shall be separate from, but shall be retained within,
(titanium stabilized: 54 hbar).
the attachment plate or strip.
S 527, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
4.3 The friction device shall not cause undue
(niobium stabilized: 54 hbar).
damage or excessive wear on the thread of the bolt.
b) Ministry of Defence specifications
The endurance test (see clause 17) shall serve to
AD 114, Design requirements,
qualification
approval
tests and
acceptance
indicate
the satisfactory
nature
of the
design in test
this
2).

for AGS 2000 series stiffnuts
(BA
and
BSF
threads)
respect.
DEF 151, Anodizing of aluminium and aluminium alloys.
DEF 2331, Protective PX-1, dyed and undyed.
DEF STAN, 03-8 Electro-deposition of tin.
2.15
stripnuts

2)

iv
2

Referred to in foreword only.
© BSI 2010
© The British Standards Institution
2013


Licensed Copy: Mr. John De

Licensed
Licensed
Licensed
Copy:
Copy:

Mr.
Copy:
Mr.
John
Mr.
John
Devaney,
John
Devaney,
Devaney,
British
British
British
Standards
Standards
Standards
Institution,
Institution,
Institution,
27/07/2012
27/07/2012
27/07/2012
10:58,
10:58,
10:58,
Uncontrolled
Uncontrolled
Uncontrolled
Copy,
Copy,

(c)
Copy,
The
(c) (c)
The
British
The
British
British
Standards
Standards
Standards
Institution
Institution
Institution
2012
2012
2012

Immediately after plating, the nuts shall be
dipped in a solution of 2 % mineral jelly in white
BS 3A 125 spirit.
to 3A 132, 3A 136 to 3A 143, 3A 147 to
BS
3A168,
125
to
3A and
132,
3A 136

3Abe
143,
3A3A
147
to
6.4
Brass
nuts
shall
uniformly
coated
3A
3A
180,
3Abronze
181,
186,
187,
192,
3A to
3A
with
tin
in accordance
with
DEF
STAN
03-8.
168,
180,

3A
181,
3A
186,
3A
187,
3A
192,
3A
193,
3A
200,
3A
201,
2A
213
to
2A
216:1981
193,
3A
200,
3A
201,
2A
213
to
2A
216:1981+A1:2013
BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to

6.5
Aluminium
nuts
shall
3A168,
193,
3A
200,3A
3Aalloy
201,
2A186,
213be
toanodically
2A 216:1981
3A
3A
180,
181,
3A
3A
187,
3A 192,
treated in accordance with DEF 151 (see note), and
3A 193,
3Aidentification
200, 3A 201,
2A 213
tobe
2A
216:1981

after
colouring,
shall
dipped
in a
lubricant complying with the requirements of
DEF 2331 or BS 3488.

3A

NOTE
Slightly
different colours will result from the different
5 Freedom from defects
7
Screw
threads
DEF STAN, 03-9 Electro-deposition
processes. of silver.
5
Freedom
from
defects
7
Screw
threads
The nuts shall be free from DTD
harmful
defects.
Allsheets

nuts. and
The strips.
screw threads shall have the
10, High
nickel copper7.1
alloy
thread
form
and
pitches
specifiedshall
in BS
1580-1
The
nuts
shall
be free
frommay
harmful
defects.
7.1
All nuts.
The screw threads
have
the &
5 Freedom
from
defects
7 Screw
threads

NOTE
Nuts
containing
defects
be deemed
not to comply
DTD
417, Lubricating
oil, aircraft controls: anti-freezing.

with
the Nuts
requirements
of defects
these standards
at any time,
BS 1580-2
1580-3,
as applicable.
thread
formand
andBS
pitches
specified
in BS 1580-1 &
NOTE
containing
be deemed
not toalthough
comply

The
nutsbeen
shall
befrom
free
frommay
harmful
defects.
7.1 All nuts. The screw threads shall have the
they
made
material
passed
released
to the
DTD
904,
Cadmium
plating.
with have
the requirements
of these
standards
atand
any
time, although
BS
1580-2
and
BS

1580-3,
as
applicable.
7.2
Steel,
corrosion-resisting
and
material
specification.
thread
form
and pitches specifiedsteel,
in BSbrass
1580-1
&
NOTE
Nuts
maypassed
be deemed
not to comply
they
have
beencontaining
made fromdefects
material
andofreleased
to Aerospace
the
3)
c) Society

British
Companies
(SBAC)
publication
bronze
nuts.
After
coating,
the
minimum
major,
7.2
Steel,
corrosion-resisting
steel,
brass
and
with
the
requirements
of
these
standards
at
any
time,
although
BS 1580-2
and BS 1580-3,
as applicable.

Text
deleted
and BS 1580-3,
as applicable.
material specification.
© BSI 2010
effective
and
minor
shall
be
not less
than
they
have been made coating
fromfinish
material
passed
released to the identification
RS
732,and
Manufacturers
monograms
for aerospace
fasteners.
bronze
nuts.
Afterdiameters
coating,
the

minimum
major,


6
Protective
7.2
Steel, corrosion-resisting
steel,nuts
brass
and
material specification.
the
minimum
dimensions
for class
specified
effective
and minor
diameters
shall2B
be not less
than

6
coating
This
publication
does
to include

all the
necessary
provisions major,
of a
6.1Protective
A protective treatment
shall
be applied
as not purport
bronze
nuts.
After
coating,
the1580-2:1962
minimum
in
Table
12 of dimensions
BS
1580-1
&
and
thefor
minimum
forBS
class 2B nuts specified
contract.
Users
are
responsible

its
correct
application.
specified
in 6.2 to
6.5. Metallic
coatings
effective and minor diameters shall be not less than
6.1
A protective
treatment
shallorbeanodic
applied
as
6 Protective
coating
Tables
46 of
BS 1580-3:1965,
as applicable.
in
Table4212and
of BS
1580-1
& BS 1580-2:1962
and

shall be applied
before
assemblyorofanodic

any non-metallic
the minimum dimensions for class 2B nuts specified
specified
in 6.2 to
6.5. Metallic
coatings
Compliance
with
a BritishTables
Standard
does
confer immunity
42 and
46 cannot
ofmaximum
BS 1580-3:1965,
asand
applicable.
6.1 A protective treatment
shall be applied
as
Before
coating,
minor
friction
but organic
coatings
(as
in 6.5)
Table

ofthe
BS
1580-1:2007
and Table
4and
and 8
in 
Table
12 of6 BS
1580-1
& BSeffective
1580-2:1962
shall
be element,
applied before
assembly
of
any
non-metallic
from legal
obligations.
specified in 6.2 to 6.5. Metallic
or anodic
coatings
diameters
shall
not
exceed
the
maximum

Before
coating,
the
maximum
effective
and
minor
of BS 1580-3:2007,
applicable. as applicable.
shall be element,
applied after
such assembly.
Tables
42 and 46 of BSas1580-3:1965,
friction
but organic
coatingsEach
(as inmetallic
6.5)
shall be applied before assembly of any non-metallic diameters
for class
2B nutsthe
specified
in Table 12 of
shall
not exceed
maximum
element
(except after
elements

be joinedEach
by welding,
shall be applied
suchtoassembly.
metallic dimensions
coating,
the
maximumand
effective
and
friction
element,
but organic
coatings
(as in 6.5)and Before
BS
1580-1
&
BS
1580-2:1962
Tables
42minor
and
dimensions
for
class
2B
nuts
specified
in Table

1246
of
brazing,
etc.)
of
floating
anchor
nuts,
stripnuts
element (except elements to be joined by welding,
diameters
shall
not
exceed
the
maximum
shall
be
applied
after
such
assembly.
Each
metallic
of
BS
1580-3:1965,
as
applicable.
1580-1 & BS 1580-2:1962 and Tables 42 and 46

cap nuts etc.)
shallofbefloating
coated anchor
(or anodized)
before and BS
brazing,
nuts, stripnuts
dimensions for class 2B nuts specified in Table 12 of
element
(except elements
to be joined
by welding,
of
1580-3:1965,
as applicable.
7.3BS
Aluminium
alloy
nuts. After
anodizing,
the46
incorporation
nut (or
assembly.
Bruising
cap
nuts shall in
bethe
coated
anodized)

before of
1580-1
& BS 1580-2:1962
and Tables
42 and
brazing, etc.) of floating anchor nuts, stripnuts and BS
screw
threads
shall
conform
to
the
class
2B
limits
plated surfacesinduring
of Bruising
elements of
is
7.3
Aluminium
alloy
nuts.
After
anodizing,
the
incorporation
the nutassembly
assembly.
of BS 1580-3:1965, as applicable.

cap nuts shall be coated (or anodized) before
and tolerances
specified
in Table
12class
of BS2B
1580-1
acceptable.
screw
threads shall
conform
to the
limits&
plated
surfaces during assembly of elements is
Aluminiumand
alloy
nuts.42
After
anodizing,
7.3
the
incorporation in the nut assembly. Bruising of
BS 1580-2:1962
Tables
and
and
tolerances specified
in Table
1246

of of
BS 1580-1 &
acceptable.
6.2
Except
as provided
in 6.3, of
steel
nuts shall
the screw
threads
shall
conform
to the
class
2B
threads
shall
conform
to
the
class
2B
limits
plated
surfaces
during for
assembly
elements
is be screw

1580-3:1965,and
as applicable.
1580-2:1962
Tables 42 and 46 of
uniformly
with cadmium
accordance
with
6.2
Exceptcoated
as provided
for in 6.3,in
steel
nuts shall
be BS
limits
and tolerances
specified
in 12
Table 6
and
tolerances
specified
in Table
of BS 1580-1 &
acceptable.
1580-3:1965,
as
applicable.
7.4

Gauges.
The
screw
threads
shall
be gauged by
DEF
STAN
03-19
BS ENin
2133.
DTD 904.
uniformly
coated
withand
cadmium
accordance with BS
BS
1580-2:1962
and
Tables
42
and
46
of
BS
1580-1:2007
and
Table
4

8
6.2 Except as provided for in 6.3, steel nuts shall be the methods described in BS 919-1. ofof
7.4
Gauges.
The
screw
threads
shall
be gauged by
DTD
904.
1580-3:1965, as applicable.
as applicable.
6.3
Corrosion-resisting
steel nutsinshall
be coated
as BS 1580-3:2007,
uniformly
coated with cadmium
accordance
with
the
methods
described
in
BS
919-1.
follows.
6.3

Corrosion-resisting
steel nuts shall be coated as 7.4 Gauges. The screw threads shall be gauged by
DTD
904.
8 Squareness of face to thread
follows.
a)
Corrosion-resisting
steelnuts
nutsshall
except
those as the methods described in BS 919-1.
6.3 Corrosion-resisting steel
be coated
8
of face
thread
8.1Squareness
General. The axis
of theto
thread
of the nut shall
complying
with the requirements
of thethose
British
a)
Corrosion-resisting
steel nuts except
follows.

beSquareness
square
to the
of thread
the nut,
within
the
8.1
General.
Thebearing
axis
of face
theto
thread
of the
nut shall
8
of face
Standards with
listedthe
in item
b) shall be
complying
requirements
of uniformly
the British
a)
Corrosion-resisting
steel
nuts except

those
tolerance
in Table
shall
be
square specified
to the bearing
face1.ofThis
the tolerance
nut, within
the
coated
withlisted
cadmium
in
accordance
with
Standards
in item
b) shall be uniformly
8.1 General. The axis of the thread of the nut shall
complying
with03-19
the requirements
of the British
be
calculated
from the
following
formula

for nuts
up
tolerance
specified
in Table
1. This
tolerance
shall
DEF
STAN
BS EN 2133.
DTD 904.
coated
with
cadmiumand
in accordance
with
be
5square to the bearing face of the nut, within the
Standards listed in item b) shall be uniformly
/
in
and
is
constant
thereafter:
to
be calculated
from the following formula for nuts up
8

DTD
904.
b)
Nuts
complying
with
followingwith
British
tolerance
specified in Table 1. This tolerance shall
coated
with
cadmium
inthe
accordance
5/ in and
is
constant thereafter:
to
8
Standards
shall
either
be
silver
plated
in
b) Nuts
complying with the following British
size formulaˆ for nuts up

be calculated
the following
squarenessfrom
Ê maximum
DTD
904.
=
¥ 0.006 ¯ + 0.003 in
Ë maximum
accordance
with either
DEF STAN
03-9,
except
across
flats
tolerance
Standards shall
be silver
plated
in that an to 5squareness
/
in
and
is
constant
thereafter:
size
8
Ê

ˆ
b) Nuts complyingin
with
the
following
British
=
with
DTDthat
904an
is
average
thickness
Ë across flats ¥ 0.006 ¯ + 0.003 in
accordance
with DEFaccordance
STAN 03-9,
except
tolerance
Standards shall
either
be by
silver
plated
in shall Notsquareness
fewer than 12
nuts shallsize
be examined
for
maximum

acceptable,
or, if03-19
required
the
purchaser,
DEF
STAN
and BS
ENwith
2133
average thickness
in accordance
DTDis904
is
= ÊË
¥ 0.006 ˆ¯ + 0.003 in
accordance
with
DEF
STAN
03-9,
except
that
an
across
flats
tolerance
squareness
of
base

to
thread
axis.
If
the
squareness
Not
fewer
than
12
nuts
shall
be
examined
for
be supplied or,
unplated:
acceptable,
if required by the purchaser,
purchaser, shall
shall
average thickness in accordance with DTD 904 is squareness
gauge
shown
in
Appendix
A
is
employed,
it

shall be
of
base
to
thread
axis.
If
the
squareness
be A
supplied
unplated:
fewer than 12 nuts shall be examined for
180
A required
192
acceptable,
or, if
by the purchaser, shall Not
used asshown
specified
in 8.2 before
of the
gauge
in Appendix
A is incorporation
employed, it shall
be
squareness
of base to thread axis. If the squareness

A
180
A 193
192
be A
supplied
unplated:
locking
181
A
used
as features.
specified in 8.2 before incorporation of the
gauge shown in Appendix A is employed, it shall be
locking
features.to check only finished nuts, these
181
193
If
it isasproposed
A
A
A 180
186
A 192
200
used
specified in 8.2 before incorporation of the
may
be

taken
from
those only
sampled
under
clause
11,
If
it
is
proposed
to check
finished
nuts,
these
locking
features.
186
200
A
181
A
193
A 187
A 201
but the
method
of testing
for squareness
shall be

may
be taken
from
those sampled
under clause
11,
If it is proposed to check only finished nuts, these
187
201
A 186
A 200
acceptable
to theofquality
authority.
but
the method
testingassurance
for squareness
shall be
Immediately
after
plating, the nuts shall be
may be taken from those sampled under clause 11,
to the quality assurance authority.
dipped
of 2 % mineral
A 187in a solution
A 201
Immediately
after

plating,
the nutsjelly
shallinbewhite acceptable
but the method of testing for squareness shall be
spirit. in a solution of 2 % mineral jelly in white
dipped
acceptable to the quality assurance authority.
Immediately after plating, the nuts shall be
6.4spirit.
Brass and
nuts
be uniformly
dipped
in a bronze
solution
of 2shall
% mineral
jelly incoated
white
with
tin inand
accordance
with
DEFbe
STAN
03-8.coated
bronze nuts
nuts
shall
be

6.4spirit.
Brass
bronze
shall
uniformly
Summary
of
pages
uniformly
withnuts
tin
in
accordance
with
with
tin incoated
accordance
with
DEF
03-8.
6.5
Aluminium
alloy
shall
beSTAN
anodically
6.4 Brass
and bronze
nuts shall
be

uniformly
coated
BS
1872
Cu/Cu/Sn/8/m.
This
document
comprises
treated
in
accordance
with
DEF
151
(see
note), anda front cover, an inside front cover, pages i to vi,
6.5
Aluminium
alloy
nuts
shall
be
anodically
with tin in accordance with DEF STAN 03-8.
pages
1be
toanodically
31
andnote),
a back

after
identification
colouring,
shall
be(see
dipped
inand
a cover.
treated
in accordance
with
DEF
151
6.5 Aluminium
alloy
nuts
shall
6.5
Aluminium
alloy
nuts
shall
be
anodically
lubricant
with
the
requirements
ofin aupdated (see copyright date) and may have had
after

identification
colouring,
shall be
dipped
This
standard
has03-25
been
treated
incomplying
accordance
with
DEF
treated
in
accordance
with
DEF
151STAN
(see note),
and
DEF
2331
or
BS
3488.
lubricant
complying
withamendments
the requirements

of
incorporated.
This will be indicated in the amendment table on the
(see
note),
and
after
identification
colouring,
after identification colouring, shall be dipped in a
DEF
2331
or BS
3488.
inside
frontfrom
cover.
NOTE
Slightly
different
colours
willcomplying
result
the
different
shall
be
dipped
in
a

lubricant
with
lubricant complying with the requirements of
processes.
NOTE
Slightly
different
colours will
result80-217
from the different
the requirements
of DEF
STAN
or
DEF
2331
or BS
3488.
processes.
BS 3488.
NOTE Slightly different colours will result from the different
processes.
3) Obtainable from the Society of British Aerospace Companies, 29 King Street, St. James’s,
London, SW1.

© BSI
BSI
2010
©
The 2010

British Standards Institution 2013
© BSI 2010

v
3
3

acce


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 193, 3A 200, 3A 201, 2A 213 to 2A 216:1981
216:1981+A1:2013

BS 2870,gauge.
RolledThe
copper
8.2 Method for using squareness
nutand copper alloys. Sheet, strip and foil.
shall be screwed by hand onBS
to 2874,
a tapered
truncated
Copper
and copper alloys.
Rods and sections (other
than

Size of stiffnuts
Diameter
of forging
screw gauge until the thread
of the nut is tight on
stock).
identification circles
the thread of the screw gauge.
sliding
sleeve, anhydrous lanolin.
in
BS A
3488,
Technical
having a face diameter equal to the minimum
No.
8-32
UNC
and
A 102, Steel bolts (Unified hexagons and Unified threads)
for aircraft.
5
distance across the flats of the corresponding
/64
No. 10-32 UNF
Corrosion-resisting
steel
bolts (Unified hexagons and Unified threads)
hexagon nut and exactly at A
90104,

to the
axis of the
1
/4 in UNF up to and
for aircraft.
screw gauge shall then be brought
into contact with
3/
7
/16 in UNF
32
the leading face of the nut, and
it shall
not be alloy boltsincluding
A 169,
Aluminium
(Unified hexagons
and Unified
threads) for
1
3
/
in
UNF
and
over
/
2
16
possible for a feeler gauge, of

thickness equal to the
aircraft.
squareness tolerance, to enter
between
B 11,
Brass the
barsleading
suitable to be brazed or silver soldered.
face of the nut and the face of the sleeve. The batch
L
80,
Sheet
and
strip
of aluminium-21/4 per cent magnesium alloy (soft-0).
of nuts shall be deemed to comply with the
L 81,
Sheet
andcomply
strip of aluminium-21/4 per cent magnesium alloy
requirements of clause 8 if the
nuts
tested
(three-quarter
hard-H6).
with the requirements of this
test. Nuts tested
under clause 8 shall not subsequently
be
released

assheet and strip of aluminium-coated
L 163, Specification for
complying with the requirements
of
these
standards
aluminium-copper-magnesium-silicon-manganese alloy (solution treated, cold
and shall be completely segregated
from
the batch
worked for
flattening
and aged
at room
temperature)
Figure
1—
Marking on hexagon stiffnuts
they represent.
(Cu 4.4, Mg 0.5, Si 0.8, Mn 0.8).
9.1.2 Stripnuts. Stripnuts of No. 8-32 UNC nominal
Table 1 — Tolerance
on squareness
L 168,
Specification for bars
and
extruded
sections
of
size

and
over shall
be marked
with the circles
alloy
(solution
treated
and
Nut size
Toleranceaaluminium-copper-magnesium-silicon-manganese
Nut size
Tolerancea
specified in 9.1.1, indented either
on the
nut body,
artificially
aged)
(not
exceeding
200
mm
diameter
or
minor
sectional
the baseplate, or the attachment strip, at the option
in
in
dimension).
of the manufacturer (see Figure 2).

No. 4-40 UNC 0.0040
S 80, Specification for high chromium-nickel corrosion-resisting steel billets,
No. 6-32 UNC 0.0045 bars, forgings and parts (880–1 080 MPa; limiting ruling section 100 mm).
steel (suitable for welding).
No. 8-32 UNC 0.0050 S192,
/2 inCarbon-manganese
UNF 0.008
No. 10-32 UNF

/2 per 0.008
cent nickel-chromium-molybdenum steel.
S995,
11UNF
/16 in

0.0050

S5112,
Semi-free
cutting carbon steel, bright bars for machining (primarily
/8 in UNF
0.009
intended for the manufacture of nuts).
5
3
/16 in UNF
0.006
/4 in UNF 0.009
S 113,
“40” carbon steel bright bars for machining (primarily intended for the

3/ in UNF
7
0.006
/8 in UNF 0.009
manufacture
of nuts).
8
7
S
114,
Manganese-molybeenum
steel.
/16 in UNF
0.007
1 in UNF 0.009
a
117, 1 per
chromium steel.
For nuts tested after assembly toSbaseplates,
thecent
tolerance
may be increased by up to 0.005 in.
S 137, Specification for high chromium-nickel corrosion-resisting steel bright
bars (free machining) (880–1 080 MPa; limiting ruling section 70 mm).
1

/4 in UNF

0.006

9 Identification and marking
1

S 154, 2 /2 per cent nickel-chromium-molybdenum steel billets, bars, forgings
Figure 2 — Marking on stripnuts
9.1 Identification of Unified
and threads
parts (880–1 080 MPa: limiting ruling section 150 mm).
9.1.1 Hexagon stiffnuts. TheSmethod
of
) (suitable
welding).
510, Carbon
steel sheet and
strip
(430–540
MN/m
9.1.3
Other
stiffnuts.
No 2marking
forfor
the
identification for hexagon nuts
of
No.
8-32
UNC
2
identification

of
Unified
threads
is
specified
for
S 511, Deep drawing carbon steel sheet and strip (280–400 MN/m ) (suitable
nominal size and over shall be
by
means
of
indented
other
than
ordinary
and
thin
hexagon
stiffnuts
as
for welding).
contiguous circles, on one or more of the hexagon
differences
in
design
render
the
other
forms
of

S 526,
Softened
18/10
chromium-nickel corrosion-resisting steel sheet and strip
flats, as shown in Figure 1. The
circles
shall be
of the
stiffnuts with Unified threads readily
(titanium
stabilized:
54
hbar).
sizes shown below.
distinguishable from their BA and BSF equivalents.
S 527,
Softened
18/10bar
chromium-nickel
corrosion-resisting
steelUnified
sheet and
strip
NOTE The circles will normally be
applied
to the hexagon
Thus, double-lug
anchor nuts with
threads
(niobium

stabilized: 54 hbar).
and will therefore appear at random
on the nuts.
are distinguishable from their BA and BSF
b) Ministry of Defence specifications
counterparts on account of the smaller distance
between
rivet holeapproval
centres; tests
the sides
the baseplate
AD 114, Design requirements,
qualification
and of
acceptance
test
2). nuts are approximately
of
Unified
single-lug
anchor
for AGS 2000 series stiffnuts (BA and BSF threads)
parallel as compared with the more triangular form
DEF 151, Anodizing of aluminium and aluminium alloys.
of the base plates of the BA and BSF nuts.
DEF 2331, Protective PX-1, dyed and undyed.
DEF STAN, 03-8 Electro-deposition of tin.
2)

iv

4

Referred to in foreword only.
© BSI 2010
© The British Standards Institution
2013


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A200,
193,3A
3A201,
200,2A
3A213
201,
to 2A 216:1981
3A 193, 3A
to2A
2A213
216:1981+A1:2013

9.2 Identification of materials
DEF STAN, 03-9 Electro-deposition of silver.
9.2.1 Steel nuts. No marking is specified.
DTD 10, High nickel copper alloy sheets and strips.
9.2.2 Corrosion-resisting steel nuts. On
DTD 417, Lubricating oil, aircraft controls: anti-freezing.

corrosion-resisting steel hexagon nuts of 1/4 in
DTD“Z”
904,
Cadmium
plating.
nominal size and over, the letter
shall
be marked
on one hexagon face to denote
corrosion-resisting
c) Society
of British Aerospace Companies (SBAC) publication 3)
steel. On corrosion-resistingRS
steel
nuts, the identification
Figure 5 monograms
— Identification
of brass
or bronze
732,anchor
Manufacturers
for aerospace
fasteners.
letter “Z” shall be marked on the nut body or on the
hexagon
nut
This publication does not purport to include all the necessary provisions of a
upper surface of the baseplate. Silver-plated
contract. Users are responsible
for Brass

its correct
application.
9.2.3
or bronze
corrosion-resisting steel nuts of 1/4 in nominal size
and over that have been Compliance
declared satisfactory
Hexagon
Brass
or bronze
hexagon nuts
with a for
British9.2.3.1
Standard
doesnuts.
cannot
confer
immunity
operation throughout thefrom
temperature
shall have a washer face on the bearing face to the
legal obligations.
range p 75 C to + 425 C shall be marked with the dimensions given in Table 6 and as shown in
letter “X” instead of, or in addition to, the letter “Z”. Figure 5.
Examples of marking on corrosion-resisting steel
9.2.3.2 Anchor nuts. On brass or bronze anchor nuts
nuts are as follows.
of 1/4 in nominal size and over, the letter “B” shall be
marked on the nut body or on the upper surface of
1) Hexagon stiffnuts and hexagon cap nuts:

the baseplate.
see Figure 3.
9.2.4 Aluminium alloy. Aluminium alloy nuts,
baseplates, nut bodies, metal caps and attachment
plates (but not attachment strips) shall be dyed blue
by an approved process.
9.3 Other markings on nut

Figure 3 — Marking on corrosion-resisting
steel hexagon nuts
2) Anchor nuts: see Figure 4.

9.3.1 All nuts of 7/16 in nominal size or over shall
have the appropriate part reference applied on one
of the hexagon faces or on the upper face of the
baseplate or attachment strip, as appropriate. The
part reference shall be that given in the part
reference column in Table 6 to Table 12, e.g. a 7/16 in
hexagon stiffnut shall bear the part reference “L”.
9.3.2 Stiffnuts of size No. 8-32 UNC and larger shall
be suitably marked with the manufacturers symbol
or letter(s), such that there is no ambiguity with any
other markings.
NOTE Manufacturers’ identification markings are shown on
SBAC
publication
RSRS732
732. .
ADS
publication

9.4 Reference identification
9.4.1 The British Standard number shall not be
marked on the nuts, but shall be used with the
relevant part reference (see Table 6 to Table 12) for
the purpose of specifying nuts on drawings or for
ordering.
NOTE Marking the appropriate BS number (e.g. A 125) on or in
relation to a product is a claim by the manufacturer that the
product has been manufactured in accordance with the
requirements of the standard. The accuracy of such a claim is
Summary of pages
therefore solely the manufacturer’s responsibility. Enquiries as
to thecover,
availability
of thirdfront
party cover,
certification
to support
This document comprises a front
an inside
pages
i to vi,such
claims should be addressed to the Director, British Standards
pages 1 to 31 and a back cover.
Institution, Maylands Avenue, Hemel Hempstead, Herts
This standard has been updated
copyright
and may
have

had
HP2(see
4SQ in
the case ofdate)
certification
marks
administered
by BSI
or towill
the appropriate
authority
other certification
marks.
amendments incorporated. This
be indicated
in theforamendment
table
on the

inside front cover.

Figure 4 — Marking on corrosion-resisting
3) Obtainable
steel anchor
nuts from the Society of British Aerospace Companies, 29 King Street, St. James’s,
London, SW1.

© BSI
BSI
2010

©
The 2010
British Standards Institution 2013

v
5


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 193, 3A 200, 3A 201, 2A 213 to 2A 216:1981
216:1981+A1:2013

BS 2870, Rolled
copper
alloys. manufacturers
Sheet, strip andshall
foil. contact the
9.4.2 If it is necessary to differentiate
on thecopper and10.2
Intending
4)
5)
or MOD(PE)
] either
drawing or order between metallic
and
non-metallic

approving
authority
[CAA (other
BS 2874,
Copper
and copper
alloys. Rods
and sections
than forging
friction element stiffnuts, the
suffixes “/66” or “/77” direct or through the BSI committee ACE/12, or
stock).
theirlanolin.
quality assurance representative, for
respectively shall be added BS
to the
standard
3488,
Technical anhydrous
reference. For example, the complete part reference information on the drawings, control documents and
A 102, Steel bolts (Unified hexagons and Unified threads) for aircraft.
testing necessary for approval purposes.
for a 1/4 in UNF steel nut with a metallic friction
104,
Corrosion-resisting
steel bolts (Unified hexagons and Unified threads)
element is “A 125 E/66”, andA for
a nut
of the same
10.3 The qualification approval tests shall consist of

aircraft.
size but with a non-metallicfor
friction
element is
all those required for normal production batch
“A 125 E/77”. A part reference
without
such a suffix
A 169,
Aluminium
alloy bolts
(Unified(see
hexagons
Unified
threads)
for and
acceptance
clausesand
12 and
13) plus
the high
shall indicate that either type
of nut may be used or low temperature tests specified in clauses 20
aircraft.
supplied.
21. Testorequipment
shall be in accordance with
B 11, Brass bars suitable toand
be brazed
silver soldered.

9.4.3 If nuts are required toLcomply
with
the
Appendix
A
and
testing
shall be carried
out on a
1
alloy (soft-0).
80, Sheet and strip of aluminium-2 /4 per cent magnesium
following British Standards, except for silver
proportion1of nuts selected as indicated in clause 11,
L 81,
Sheet and
strip of aluminium-2
/4 per cent magnesium
alloy and to the
plating, the suffix “/UP” shall
be added
to the
from a representative
production batch
(three-quarter
hard-H6).
standard reference:
satisfaction of the quality assurance authority.
L 163, Specification for sheet
and

strip
of aluminium-coated
A 180
A 192
10.4
The
qualification
approval shall be subject to
aluminium-copper-magnesium-silicon-manganese
alloy (solution
treated,
cold
periodic
review
by the quality
assurance
authority
A 181
A 193
worked for flattening and aged
at room temperature)
and automatically
when any change is made in the
A 186
A 200
(Cu 4.4, Mg 0.5, Si 0.8, Mnmaterial,
0.8).
dimensions or manufacturing process.
L 168, Specification for bars and extruded sections of
A 187

A 201
aluminium-copper-magnesium-silicon-manganese
alloyacceptance
(solution treated and
steel 11 Production batch
For example, a 5/16 in UNF corrosion-resisting
artificially
aged)
(not
exceeding
200
mm
diameter
or
minor
sectional
thin, double-lug, floating anchor nut, unplated is
Before release by the manufacturer, a random
dimension).
“A 193 G/UP”.
sample containing 100 nuts shall be taken from
S 80,/) Specification
for higheach
chromium-nickel
steel
billets,
batch of 1 000corrosion-resisting
or more nuts of each
size.
These

9.4.4 The use of the solidus (i.e.
in part references
bars,
forgings
and
parts
(880–1
080
MPa;
limiting
ruling
section
100
mm).
batches shall be limited to 100 000 nuts. A random
may be waived when automatic data processing
sample
containing
25 nuts shall be taken from each
S 92, Carbon-manganese
(suitable
for welding).
techniques are used in part reference
identification. steel
batch
of
less
than
1
000

nuts of each size.
1
In such cases, dashes (i.e. -)Smay
be
used
steel.
95, 1 /2 per cent nickel-chromium-molybdenum
(e.g. A 125E-66) or elements of the part reference
Nuts with integral baseplates, when required for
S 112, Semi-free
steel, bright bars for machining (primarily
may be shown without separating
features cutting carbon
stripnuts, shall be subject to the above procedure
intended
for
the
manufacture
of
nuts).
(e.g. A125E66)
before insertion in the strip. In addition, the strip
S 113,
“40” carbon
for machining
(primarily
intended
for the
and bars
the assembly

of nuts
therein shall
receive
9.5 Packaging. All nuts shall
be made
into steel bright
manufacture
of
nuts).
packages, the labels of which shall clearly state the individual inspection.
S 114,
Manganese-molybeenum
steel.
appropriate British Standard
(see Table
5), followed
12
Inspection
of samples
by the part reference (see Table
6 to
Table
and
S 117,
1 per
cent12)
chromium
steel.
the manufacturer’s name. S 137, Specification for high
Each

nut in the sample
taken in accordance
with
chromium-nickel
corrosion-resisting
steel bright
clause
11
shall
be
inspected
for
compliance
with
the
bars (free machining) (880–1 080 MPa; limiting ruling section 70 mm).
Section 2. Inspection and testing
requirements
of
3.1,
clauses
5,
7
and
9
and
with
the
S 154, 21/2 per cent nickel-chromium-molybdenum steel billets, bars, forgings
requirements of the approved drawings. Inspection

and
parts (880–1 080 MPa: limiting ruling section 150 mm).
10 Qualification approval
of nuts for squareness shall be in accordance with
2) (suitable for welding).
510, Carbon
sheet and
strip8.(430–540
MN/m
clause
The batch
of nuts
shall be deemed to
10.1 Stiffnuts shall only be S
supplied
understeel
these
2) sample
(suitableis
S 511, Deep
carbon
steel sheet
strip (280–400
MN/m
comply
with and
the foregoing
clauses
if the
standards numbers if manufactured

anddrawing
tested in
for welding).
accordance with these standards
by a manufacturer proved to comply.
holding qualification approval.
Such
approval
is chromium-nickel corrosion-resisting steel sheet and strip
S 526,
Softened
18/10
13 Testing of samples
only granted to the manufacturer
whostabilized:
has a
(titanium
54 hbar).
satisfactory quality control S
organization
and
has chromium-nickel
One series ofcorrosion-resisting
tests in accordance
with
527, Softened
18/10
steel
sheet and strip
carried out qualification approval

testing
to
clauses
15,
16,
17,
18
and
19
shall
be carried out for
(niobium stabilized: 54 hbar).
demonstrate the effectiveness of the proprietary
each batch of nuts sampled under clause 11.
b) Ministry
of Defence specifications
design as produced by a declared
manufacturing
The 18 nuts for the tests shall be taken at random
AD 114, Design requirements,
approval
tests and acceptance test
process.
fromqualification
those inspected
under
2). clause 12. The batch of
for AGS 2000 series stiffnuts
(BA
and

BSF
threads)
nuts shall be deemed to comply with the foregoing
DEF 151, Anodizing of aluminium
alloys.to comply.
clauses ifand
thealuminium
sample is proved
DEF 2331, Protective PX-1, dyed and undyed.
DEF STAN, 03-8 Electro-deposition of tin.
4) Civil Aviation Authority, Brabazon House, Redhill, Surrey, RH1 1SQ.
5) Ministry of Defence Procurement Executive, Aeronautical Quality Assurance

UB9 6 BB.

iv
6

2)

Directorate, Harefield, Uxbridge, Middlesex,

Referred to in foreword only.
© BSI 2013
2010
© The British Standards Institution


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A200,
193,3A
3A201,
200,2A
3A213
201,
to 2A 216:1981
3A 193, 3A
to2A
2A213
216:1981+A1:2013

Samples of nuts normally silver plated but required
Table 2 — Unscrewing torque
DEF
Electro-deposition of silver.
to be supplied unplated, shall
be STAN,
plated 03-9
for the
Unscrewing torque
DTD 10, High nickel copper alloy sheets and strips.
purpose of these tests.
Aluminium
Medium tensile
Size ofcontrols:
stiffnut anti-freezing.
alloy, brass and

steel and
DTD
417,
Lubricating oil, aircraft
Nuts tested under this clause
shall
not
bronze nuts
corrosion-resisting
subsequently be released asDTD
complying
with the plating.
904, Cadmium
steel nuts
a
requirements of these standards
and of
shall
be Aerospace Companies (SBAC)
ozf inpublication
lbf inb 3) ozf ina
lbf inb
c) Society
British
completely segregated from the batch they
No. 4-40 monograms
UNC 2.2 for aerospace fasteners.
1.1
RS 732, Manufacturers identification
represent.

No.
6-32
UNC
4.3
2.2 of a
This publication does not purport to include all the necessary provisions
8-32
UNCapplication.
6.6
3.3
contract. Users are responsibleNo.
for its
correct
14 Test bolts
No. 10-32 UNF 9.0
4.5
Except for the bolt tolerance
test, the tests
Compliance
withshall
a British Standard does cannot confer immunity
1
/4 in UNF
1.3
11.0
either be performed on unused
bolts complying
with
from legal
obligations.

5/
the requirements of the British Standards indicated
2.4
1.2
16 in UNF
3
in the following table or, with the agreement of the
/8 in UNF
4.0
2.0
quality assurance authority, test studs of the
7/
6.1
3.1
16 in UNF
material and with the screw threads and finish
1
/2 in UNF
8.8
4.4
specified in British Standards A 102, A 104 or A 169,
9/
as appropriate, shall be used. The bolts or studs
12.4
6.2
16 in UNF
shall be clean and dry before test.
5
/8 in UNF
16.4

8.2
BS no.
To be used for tests on
3/
in
UNF
27.0
13.5
4
A 102
Cadmium-plated steel and
7
/8 in UNF
41.5
20.0
corrosion-resisting steel nuts and brass or
1 in UNF
60.0
30.0
bronze nuts
a
–3
A 104

Silver-plated corrosion-resisting steel
nuts

A 169

Aluminium alloy

allownuts
nuts

b

ozf in = 7.061 55 10 N m (7061.55 4N m)
1 lbf in = 0.112 985 N m.

16 Bolt tolerance test

Six nuts of sizes other than No. 4-40 UNC and
No. 6-32 UNC, taken at random from the balance
of the test sample, shall each be screwed five
times completely on and off a dry high limit test
bolt. Each time at least three threads of the bolt
15 Torque test
shall protrude beyond the friction element of the nut
15.1 Six nuts shall be taken at random from the test before the latter is unscrewed and any swarf
sample of clause 13 and each shall be mounted on an generated shall be removed from the threads before
unused dry bolt (see clause 14). The average torque reversal of test bolt rotation.
to resist unscrewing shall be measured through at
The same nuts shall then be screwed in turn on to a
least three turns at a uniform speed between 2 r/min
dry low limit test bolt, when the average unscrewing
and 30 r/min, the static torque being ignored.
torque shall be measured through at least three
15.2 Using the same nut on the same bolt as
complete turns at a uniform speed between 2 r/min
specified in 15.1, the unscrewing torque shall again and 30 r/min, the static torque being ignored.
be measured after complete immersion of bolt and

The average unscrewing torque for the six nuts
nut in a light oil (such as that specified in
tested shall be not less than 40 % of the
DTD 417) for a period of not less than 1 min.
corresponding value specified in Table 2, and the
The average of the six dry and the average of the six minimum value shall be not less than 25 % of that
oiled unscrewing torque readings shall each be not
specified.
less than the appropriateSummary
values specified
in
of pages
Nuts shall be visually examined for cracking of the
Table 2, and in addition, This
the minimum
documentindividual
comprises a front
cover,
an inside
cover,
pages itest.
to vi,If
locking
feature
afterfront
the bolt
tolerance
unscrewing torque reading
shall
be31

notand
lessa back cover.
pages
1 to
cracking is present, the whole batch shall be deemed
than 75 % of the tabulated value.
not (see
to comply
withdate)
the requirements
these
This standard has been updated
copyright
and may haveofhad
standards.
amendments incorporated. This
will be indicated in the amendment table on the
inside front cover.
The special bolts used in this test shall be as defined
in Appendix A.
For the bolt tolerance test (see clause 16), hardened
and ground steel, unplated bolts or studs shall be
used.

3) Obtainable

from the Society of British Aerospace Companies, 29 King Street, St. James’s,
London, SW1.

© BSI

BSI
2010
©
The 2010
British Standards Institution 2013

v
7


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 193, 3A 200, 3A 201, 2A 213 to 2A 216:1981
216:1981+A1:2013

BS 2870, Rolled copper and19
copper
alloys.
Sheet,
strip andnuts)
foil.
Thrust
test
(anchor
BS 2874, Copper and copper alloys. Rods and sections (other than forging
For sizes other than No. 4-40 UNC and
Three nuts shall be taken from the sample
stock).

No. 6-32 UNC, the six nuts remaining from the test (they may be nuts previously tested under
BSon
3488,
anhydrous
lanolin.
sample shall each be screwed
to a Technical
dry standard
clauses
15, 16 and 17) and secured to a rigid steel
A 102,
bolts
(Unified plate
hexagons
and Unified
threads)
for aircraft.
bolt for at least three turns after
theSteel
friction
element
by screws,
the head
diameter
of which shall
starts to engage, and so thatA at
least
one
complete
not

exceed
that
of
the
appropriate
rivet
head.
An
104, Corrosion-resisting steel bolts (Unified hexagons and Unified
threads)
thread protrudes beyond the
element. The
axial load of the relevant value specified in Table 3
forfriction
aircraft.
nut shall then be unscrewed until the friction
shall then be applied through the rigid plate by
A 169, Aluminium alloy bolts (Unified hexagons and Unified threads) for
element is completely disengaged. Any swarf
means of a spherical-ended mandrel of a diameter
aircraft.
generated shall be brushed away after each cycle.
equal to the major diameter of the thread of the nut
B 11,
Brass
bars
suitable
silver
soldered.
The cycle shall be repeated 30

times,
after
which
the totobebebrazed
tested.orThe
hole
in the plate shall be 10 %
torque test of 15.1 shall be repeated
and
in no
case
larger than1/4the
diameter.alloy
The (soft-0).
assembly
permandrel
cent magnesium
L 80, Sheet
and
strip
of aluminium-2
shall the final torque be lessLthan
50
%
of
the
shall
be
deemed
not

to
have
complied
with
the
1
81, Sheet and strip of aluminium-2 /4 per cent magnesium alloy
required unscrewing torque(three-quarter
specified in Table
2.
requirements
of
these
standards
if
a
permanent
set
hard-H6).
greater than one thread pitch has developed along
L 163,
of nut.
aluminium-coated
18 Torsional strength
testSpecification
(anchor for sheet
theand
axisstrip
of the
aluminium-copper-magnesium-silicon-manganese alloy (solution treated, cold

nuts and stripnuts)
worked for flattening and aged
at room
temperature) test
20 High
temperature
Three nuts shall be taken from
(Cu the
4.4, sample
Mg 0.5,(they
Si 0.8, Mn 0.8).
Six nuts of each size, mounted on dry standard bolts
may be nuts previously tested
under
clauses 15,for
16 bars
L 168,
Specification
and extruded sections of
(see clause 14), shall be:
and 17) and located on a rigid
base
by
means
of
aluminium-copper-magnesium-silicon-manganese alloy (solution treated and
dowels through the rivet holes.
A torque
shall
then

a) submitted
to a torque
test (see
15.1), when the
artificially
aged)
(not
exceeding
200 mm diameter
or minor
sectional
be applied on the nut body, dimension).
without axial load,
values obtained shall be at least equal to the
either direct or by means of a bolt or stud. Single-lug
appropriate torque values specified in Table 2;
corrosion-resisting steel billets,
anchor nuts shall be tested S
by80,
theSpecification
use of a boltfor
or high chromium-nickel
b) uniformly
heated toruling
a minimum
bars,
forgings
and
parts
(880–1

080
MPa;
limiting
section temperature
100 mm).
stud, the lateral movement of which shall be
of:
S 92,values
Carbon-manganese
suitably restrained. The torque
specified in steel (suitable for welding).
1) + 425 C, for corrosion-resisting steel nuts,
1
Table 3 shall be obtained without
failure.
steel.
S 95, 1 /2 per cent nickel-chromium-molybdenum
silver plated;
Table 3 — Torsional strength
(anchor cutting
nuts carbon steel, bright bars for machining (primarily
S 112, Semi-free
2) + 200 C, for steel and corrosion-resisting
and stripnuts) and thrust
test
intended
for loads
the manufacture of steel
nuts).nuts, cadmium plated;
(anchor nuts)

S 113, “40” carbon steel bright bars
(primarily
intended
3) +for
125machining
C, for aluminium
alloy,
brassfor
andthe
Torsional strength
Thrustoftest
load
manufacture
nuts).
bronze nuts;
Size of stiffnut
Brass,
Brass,
S 114, Steel
Manganese-molybeenum
steel.
Steel
maintained
at that temperature for a period
aluminium
aluminium
S
117,
1
per

cent
chromium
steel.
of
2
h,
and
submitted
to a further torque test
lbf ina
lbf ina
lbfb
lbfb
(see
15.1)
while
at
that
temperature,steel
when
the
S 137, Specification for high chromium-nickel corrosion-resisting
bright
No. 4-40 UNC 10
4 bars (free
30 machining)
18
average
torque
value

shall
be
not
less
than
(880–1 080 MPa; limiting ruling section 70 mm). 75 %
of that specified in Table 2;
No. 6-32 UNC 20
8 S 154, 50
30cent nickel-chromium-molybdenum
steel billets, bars, forgings
21/2 per
c)
after
cooling
to
room
temperature,
submitted to
and
parts
(880–1
080
MPa:
limiting
ruling
section
150
mm).
No. 8-32 UNC 30

12
65
40
a further torque test, when
the average value
2
Carbon
strip (430–540 MN/m ) (suitable for welding).
No. 10-32 UNF 40
16 S 510, 80
50 steel sheet andobtained
shall be not less than 75 % of that
S 511, Deep drawing carbon steel
sheetin
and
strip2.(280–400 MN/m2) (suitable
specified
Table
1
70
30 for welding).
80
50
/4 in UNF
Nuts normally silver plated but required to be
5/
Softened
corrosion-resisting
steel
and strip

100
40 S 526, 80
50 18/10 chromium-nickel
supplied unplated
shall be plated
forsheet
the purpose
of
16 in UNF
(titanium
stabilized:
54
hbar).
this
test.
3
150
60
80
50
/8 in UNF
S 527, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
7
200
80 (niobium
80 stabilized:
50
/16 in UNF
54 hbar).
1

/2 in UNF
250 100 b) Ministry
80 of
50Defence specifications
a
AD 114, Design requirements, qualification approval tests and acceptance test
1 lbf in = 0.112 985 N m.
b
1 lbf = 4.448 22 N.
for AGS 2000 series stiffnuts (BA and BSF threads)2).
DEF 151, Anodizing of aluminium and aluminium alloys.
DEF 2331, Protective PX-1, dyed and undyed.
DEF STAN, 03-8 Electro-deposition of tin.

17 Endurance test

2)

iv
8

Referred to in foreword only.
© BSI 2013
2010
© The British Standards Institution


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to

3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A200,
193,3A
3A201,
200,2A
3A213
201,
to 2A 216:1981
3A 193, 3A
to2A
2A213
216:1981+A1:2013

21.2 A further six nuts of each size and the
21 Low temperatureDEF
testSTAN, 03-9 Electro-deposition
of silver.

corresponding dry standard bolts (see clause 14)
21.1 Six nuts of each size, mounted
dry nickel
standard
DTD 10,on
High
coppershall
alloybesheets
andtostrips.
reduced
a temperature of – 40 C,
bolts (see clause 14), shall be:

assembled
at thatanti-freezing.
temperature, and submitted to
DTD 417, Lubricating oil, aircraft
controls:
a) submitted to a torque test (see 15.1) at room
the tests specified in 21.1 c) and 21.1 d).
DTD 904, Cadmium plating.
temperature, when the values obtained shall be
21.3Companies
Nuts normally
silver
plated but
required to be
3)
c) Societytorque
of British
Aerospace
(SBAC)
publication
at least equal to the appropriate
values
supplied unplated shall be plated for the purpose of
specified in Table 2;
RS 732, Manufacturers identification
this test. monograms for aerospace fasteners.
b) reduced to a temperature
of – 75 C, does not purport to include all the necessary provisions of a
This publication
maintained at that temperature

for a period
contract. Users
are responsible
its correct application.
22for
Pressure
test for cap nuts
of 20 min, and submitted to a further torque test
Six
nuts taken
at random
theimmunity
test sample shall
with and
a British
Standard
does
cannot from
confer
(see 15.1) while still atCompliance
that temperature
in
be
assembled
to
fixtures
approved
by the quality
from
legal

obligations.
conditions free from hoar frost, when the average
assurance
authority
and
subjected
to a hydraulic
value obtained shall be at least 90 % of that
2
(690 kPa) for
and
pneumatic
pressure
of
100
lbf/in
specified in Table 2;
a period of 5 min. There shall be no leakage at the
c) raised to a temperature of – 40 C, at which
cap retention section.
temperature the nut shall be screwed on and off
the bolt between the tightened position and that
in which the friction element is completely
disengaged from the bolt thread, there being at
least three turns between these positions; this
cycle shall be repeated three times;
d) after returning to room temperature,
submitted to a further torque test, when the
average value obtained shall be not less
than 75 % of that specified in Table 2.

Summary of pages
This document comprises a front cover, an inside front cover, pages i to vi,
pages 1 to 31 and a back cover.
This standard has been updated (see copyright date) and may have had
amendments incorporated. This will be indicated in the amendment table on the
inside front cover.

3) Obtainable

from the Society of British Aerospace Companies, 29 King Street, St. James’s,
London, SW1.

© BSI
BSI
2010
©
The 2010
British Standards Institution 2013

v
9


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 193, 3A 200, 3A 201, 2A 213 to 2A 216:1981
216:1981+A1:2013

BSMaterials
2870, Rolled
and(Unified
copper alloys.
Sheet,for
strip
and foil.
Table 4 —
forcopper
stiffnuts
threads)
aircraft
BS 2874, Copper and copper alloys.
Rods
and sections
(other
Material
specification
(latest
issue)than forging
Usedstock).
on British
CorrosionComponent parts
Standard
stiffnuts
Brass or bronze nuts
Steelanhydrous
nuts
resisting

BS 3488,
Technical
lanolin.steel Aluminium
alloy nuts
nuts
A 102, Steel bolts (Unified hexagons and Unified threads) for aircraft.
BS
EN 12163
Nut body
A 125Ato
A 132,
S 80bolts
or (Unified L
168
B 11,
S 92,
104,
Corrosion-resisting
steel
hexagons
and
Unified
threads)
(CW712R
R400)
(and baseplate
A 136for
toaircraft.
A 143, S 95,
S 137

BS 2874-CZ
112,
a
BS EN
12164114,
if in one piece)
A 147 to A 168, S 154,
2874-CZ
AA
169,
Aluminium
threads)
for
A 180,
181,
BS 2874-CZ
121,
S 112b,alloy bolts (Unified hexagons and Unified
(CW720R
R440)
aircraft.
c
S 113 ,
A 186, A 187,
2874-CZ
BS EN
12167122 or
d
BA
11,193,

Brass bars
suitable
to be brazed or silver soldered. (CW614N
or
S 114
R360),
A 192,
BS 2874-PB
102
d
(CW720R
R390),
S 117
A 200,
alloy (soft-0).
LA
80,201,
Sheet and
strip of aluminium-21/4 per cent magnesium
(CW452K R420)
A 213 to A 216
L 81, Sheet and strip of aluminium-21/4 per cent magnesium alloy
Baseplate
A 136(three-quarter
to A 143, S hard-H6).
510 or
DTD 10,
L 163
BS 2870-CZ
112

BS
EN 1652
(if made from sheet) A 147 to A 168, S 511
S 526 or
(CW508L
R350)
L 163, Specification for sheet and strip of aluminium-coated
(fixed anchor,
A 186, A 187,
S 527
aluminium-copper-magnesium-silicon-manganese alloy (solution treated, cold
floating anchor
A 192, A 193,
worked for flattening and aged at room temperature)
and stripnuts)
A 200, A 201,
(Cu 4.4, Mg 0.5, Si 0.8, Mn 0.8).
A 215 and A 216
L 168, Specification for bars and extruded sections of
Metal cap
A 213aluminium-copper-magnesium-silicon-manganese
to A 216 S 510 or
—
L 80alloy (solution
—
treated and
S
511
artificially aged) (not exceeding 200 mm diameter or minor sectional
Attachment plate

A 147dimension).
and A 148 S 510 or
—
—
—
(steel)
S 511 for high chromium-nickel corrosion-resisting steel billets,
S 80, Specification
(floating anchor
bars, forgings and parts (880–1 080 MPa; limiting ruling section 100 mm).
nuts)
S 92, Carbon-manganese steel (suitable for welding).
Attachment plate
A 149,
A 150,
DTD 10,
— steel.
—
cent nickel-chromium-molybdenum
S 95,
11/2 per—
(corrosion-resisting) A 192 and A 193
S 526 or
S 112, Semi-free cutting carbon
steel, bright bars for machining (primarily
S 527
intended for the manufacture of nuts).
Attachment plate
A 151 to A 154 L 163 or
—

L 163 or —
S 113, “40” carbon
(aluminium alloy)
L 81 steel bright bars for machining
L 81(primarily intended for the
manufacture of nuts).
BS
EN 1652
Attachment plate
A 155 and A 156 —
—
—
BS 2870-CZ
112
S 114, Manganese-molybeenum steel.
(CW508L R350)
(brass)
S 117, 1 per cent chromium steel.
Attachment strip
A 165 to A 168 S 511
—
S 511
—
S 137, Specification for high chromium-nickel corrosion-resisting steel bright
(stripnuts)
bars (free machining) (880–1 080 MPa; limiting ruling section 70 mm).
a

If the ruling section of the specified material does not permit the manufacture of the nut body and baseplate in one piece, S 113
perand

cent
nickel-chromium-molybdenum
steel billets, bars, forgings
21S/2 112
and S 114 materials may be used S
in 154,
place of
S 113
materials respectively.
For fixed anchor, floating anchor and
where the
joining theruling
nut body
to a separate
baseplate is to be welding,
andstripnuts,
parts (880–1
080method
MPa:oflimiting
section
150 mm).
S 92 material shall be used for all nuts of sizes 1/4 in UNF to 1/2 in UNF inclusive, and may be used for
nuts of sizes below 1/4 in UNF.
2
) (suitable
for welding).
510,
Carbon
sheet and
strip (430–540

MN/m
For nuts 1/4 in UNF to 1/2 in UNF, SS92
material
shallsteel
be hardened
and tempered
to a tensile
strength
of not less than
45 tonf/in2 and
2
not more than 55 tonf/in2.
S 511, Deep drawing carbon steel sheet and strip (280–400 MN/m ) (suitable
b All sizes up to and including 1/ in.
4
for
welding).
c
1
All sizes up to and including /2 in.
d
S 526, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
All sizes.

(titanium stabilized: 54 hbar).
S 527, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(niobium stabilized: 54 hbar).
b) Ministry of Defence specifications
AD 114, Design requirements, qualification approval tests and acceptance test
for AGS 2000 series stiffnuts (BA and BSF threads)2).

DEF 151, Anodizing of aluminium and aluminium alloys.
DEF 2331, Protective PX-1, dyed and undyed.
DEF STAN, 03-8 Electro-deposition of tin.

2)

iv
10

Referred to in foreword only.
© BSI 2013
2010
© The British Standards Institution


Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A200,
193,3A
3A201,
200,2A
3A213
201,
to 2A 216:1981
3A 193, 3A
to2A
2A213
216:1981+A1:2013

Table 5 — Stiffnut types and British Standard numbers, with temperature classification
DEF STAN, 03-9 Electro-deposition of silver.
Stiffnut type
Dimension
Temperature classification
DTD 10, High nickel
copper alloy sheets and strips.
table no.
p 75 C to p 75 C to p 75 C to p 75 C to p 75 C to
DTD 417, Lubricating oil, aircraft
+ 200 Ccontrols:
+ 200 anti-freezing.
C
+ 425 C
+ 125 C
+ 125 C
DTD 904, Cadmium plating.
British Standard numbers
3)
c) Society of British Aerospace
(SBAC) publication
SteelCompanies
nuts
Corrosion-resisting
Aluminium
Brass or
(cadmium
steel nuts
alloy nuts

bronze
RS 732, Manufacturers identification
monograms for aerospace
fasteners.
plated)
(anodized)
(tinned)
a
Cadmium
Silver
This publication does not purport to include
all the
necessary
provisions of a
plated
(or
plated
unplated)
contract. Users are responsible for its correct application.
Hexagon
Ordinary
A 125
A 127
A 180
A 129
A 131
Compliance with6a British Standard does cannot confer immunity
A 128
A 181
A 130

A 132
from Thin
legal obligations. A 126
Cap
Double-lug fixed
anchor

Ordinary
Thin
Cap

Double-lug with steel
Ordinary
floating
attachment plate Thin
anchor
with corrosion- Ordinary
resisting steel
Thin
attachment plate
with aluminium Ordinary
alloy attachment Thin
plate

7
8
9

10

with brass
Ordinary
attachment plate Thin
Single-lug fixed
anchor

Ordinary

Strip

Ordinary

Thin
Thin

a

11
12

A 213

—

—

A 214

—

A 136

A 138

A 186

A 140

A 142

A 137

A 139

A 187

A 141

A 143

A 215

—

—

A 216

—

A 147

—

—

—

—

A 148

—

—

—

—

—

A 149

A 192

—

—

—

A 150

A 193

—

—

A 151

—

—

A 153

—

A 152

—

—

A 154

—

—

—

—

—

A 155

—

—

—

—

A 156

A 157

A 159

A 200

A 161

A 163

A 158

A 160

A 201

A 162

A 164

A 165

—

—

A 167

—

A 166

—

—

A 168

—

These nuts are of all metal construction only.

Summary of pages
This document comprises a front cover, an inside front cover, pages i to vi,
pages 1 to 31 and a back cover.
This standard has been updated (see copyright date) and may have had
amendments incorporated. This will be indicated in the amendment table on the
inside front cover.

3) Obtainable

from the Society of British Aerospace Companies, 29 King Street, St. James’s,
London, SW1.

© BSI
BSI
2010
©
The 2010
British Standards Institution 2013

v
11


1.240 1.230
1.427 1.417
0.040
0.040
0.835

0.953

0.732
0.857
0.920
1.043
0.742
0.867
0.930
1.053
0.030
0.030
0.035
0.035
0.514
0.558
0.623
0.746

0.421
0.483
0.545
0.670
0.431
0.493
0.555
0.680
0.020
0.020
0.025

0.025

0.010
0.010
0.015
0.015
0.143
0.179
0.233
0.241

0.273
0.326
0.386
0.445

0.173
0.235
0.297
0.329
0.183
0.245
0.307
0.339

min.
in

Diameter S

max.
in

Depth
P
0.005
in
Thin
nut
max.
in

12

10
11
Overall height
L

0.490 1.085
0.573 1.245
0.740
0.865
0.480
0.563

0.660
0.725
0.810
0.975

0.281
0.323
0.365
0.448
0.427
0.490
0.552
0.677

0.340
0.410
0.490
0.570
0.123
0.156
0.198
0.240
0.190
0.240
0.302
0.365

S 95, 11/2 per cent nickel-chromium-molybdenum steel.

0.271
0.313
0.355
0.438

0.053

0.069
0.093
0.103

0.113
0.146
0.188
0.230

0.175
0.215
0.275
0.285
0.063
0.079
0.103
0.113
0.095
0.115
0.145
0.157

min.
in
min.
in

Ordinary nut
Thin nut

6
7
Height of hexagon
including washer face,
if any)
X

8
9
Thread length
G

L 81, Sheet and strip of aluminium-21/4 per cent magnesium alloy
(three-quarter hard-H6).
L 163, Specification for sheet and strip of aluminium-coated
aluminium-copper-magnesium-silicon-manganese alloy (solution treated, cold
worked for flattening and aged at room temperature)
(Cu 4.4, Mg 0.5, Si 0.8, Mn 0.8).
L 168, Specification for bars and extruded sections of
aluminium-copper-magnesium-silicon-manganese alloy (solution treated and
artificially aged) (not exceeding 200 mm diameter or minor sectional
dimension).
S 80, Specification for high chromium-nickel corrosion-resisting steel billets,
bars, forgings and parts (880–1 080 MPa; limiting ruling section 100 mm).
S 92, Carbon-manganese steel (suitable for welding).

0.730
0.855
1.443
1.660

0.417
0.480
0.542
0.667
0.866
1.010
1.083
1.227

0.180
0.230
0.292
0.355
0.505
0.577
0.650
0.794

0.085
0.105
0.135
0.147
0.217
0.289
0.361
0.397

Ordinary nut

min.
in
max.
in

5
Width
across
corners
C

S 112, Semi-free cutting carbon steel, bright bars for machining (primarily
intended for the manufacture of nuts).
S 113, “40” carbon steel bright bars for machining (primarily intended for the
manufacture of nuts).
S 114, Manganese-molybeenum steel.
S 117, 1 per cent chromium steel.
S 137, Specification for high chromium-nickel corrosion-resisting steel bright
bars (free machining) (880–1 080 MPa; limiting ruling section 70 mm).

a

Non-preferred.

1.240
1.426
1.250
1.438
0.8750 U
1.0000 W

/8 in UNF
1 in UNF
7

0.750
0.875
0.938
1.062
N
P
Q
S
0.5000
0.5625
0.6250
0.7500

in UNF
/16 in UNF
5
/8 in UNF
3/ in UNF
4
1

/2
a9

0.741
0.866

0.929
1.052

0.431
0.493
0.554
0.679
E
G
J
L
0.2500
0.3125
0.3750
0.4375
5

1

/4 in UNF
/16 in UNF
3
/8 in UNF
7/
16 in UNF

0.438
0.500
0.562
0.688

0.183
0.245
0.307
0.339
A
B
C
D

0.188
0.250
0.312
0.344

min.
in
in

max.
in

0.1120
0.1380
0.1640
0.1900

Referred to in foreword only.

No. 4-40 UNC

No. 6-32 UNC
No. 8-32 UNC
No. 10-32 UNF

NOTE

For convenience ordinary nuts only are illustrated.
1
2
3
4
Nominal size
Part
Width across
reference
flats
B

S 154, 21/2 per cent nickel-chromium-molybdenum steel billets, bars, forgings
and parts (880–1 080 MPa: limiting ruling section 150 mm).
S 510, Carbon steel sheet and strip (430–540 MN/m2) (suitable for welding).
S 511, Deep drawing carbon steel sheet and strip (280–400 MN/m2) (suitable
for welding).
S 526, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(titanium stabilized: 54 hbar).
S 527, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(niobium stabilized: 54 hbar).
b) Ministry of Defence specifications
AD 114, Design requirements, qualification approval tests and acceptance test
for AGS 2000 series stiffnuts (BA and BSF threads)2).

DEF 151, Anodizing of aluminium and aluminium alloys.
DEF 2331, Protective PX-1, dyed and undyed.
DEF STAN, 03-8 Electro-deposition of tin.
2)

iv
12

Thin Ordinary
nut
nut
min.
max.
in
in

13
14
Washer face
(brass and bronze
nuts only)

BS 2870, Rolled copper and copper alloys. Sheet, strip and foil.
BS 2874, Copper and copper alloys. Rods and sections (other than forging
stock).
BS 3488, Technical anhydrous lanolin.
A 102, Steel bolts (Unified hexagons and Unified threads) for aircraft.
A 104, Corrosion-resisting steel bolts (Unified hexagons and Unified threads)
for aircraft.
A 169, Aluminium alloy bolts (Unified hexagons and Unified threads) for

aircraft.
B 11, Brass bars suitable to be brazed or silver soldered.
L 80, Sheet and strip of aluminium-21/4 per cent magnesium alloy (soft-0).

Table 6 — Dimensions and part references of ordinary and thin hexagon stiffnuts (A 125 to A 132, A 180 and A 181)

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
BS 3A 125 to 3A 132, 3A 136 to 3A 143,
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 147 to 3A 168, 3A 180, 3A 181, 3A 186,
3A 193, 3A 200, 3A 201, 2A 213 to 2A 216:1981
216:1981+A1:2013
3A 187, 3A 192, 3A 193, 3A 200, 3A 201,
2A 213 to 2A 216:1981

© BSI
BSI 2010
2010
©
© The British Standards Institution
2013

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The


0.612
0.329

0.440

0.535
0.266

0.206

in
in

X

max.
max.

0.319

0.256

0.196

D

min.

Diameter

13

Bolt thread

length

12

Counterbore

Dimension X (column 13), allowing for the stiffnut in its minimum condition, is the maximum bolt thread length that can be accommodated in the nut.
NOTE 2

NOTE 3 It will be necessary for a washer to be used under the hexagon nut body or else the protrusion of bolt thread above the receiving plate shall be controlled within the
specified X dimension.

On this nut, thread length G is less than that of the ordinary hexagon nut A 125 (see Table 6) by the amount of 0.050 in counterbore.
NOTE 1

DEF STAN, 03-9 Electro-deposition of silver.
DTD 10, High nickel copper alloy sheets and strips.
DTD 417, Lubricating oil, aircraft controls: anti-freezing.
DTD 904, Cadmium plating.
c) Society of British Aerospace Companies (SBAC) publication 3)
RS 732, Manufacturers identification monograms for aerospace fasteners.
This publication does not purport to include all the necessary provisions of a
contract. Users are responsible for its correct application.

0.050
0.445
0.570
0.688
0.190
0.577

0.493

0.050

0.050
0.310

0.360
0.490

0.400
0.500

0.600
0.140

0.107
0.397

0.505
0.431

0.339

in
in
in
in
in
in

in
in

min.

0.500
G
0.3125

0.438
E
0.2500

0.344
D
No. 10-32 UNF 0.1900

in

Depth

Q
K

max.
min.

H
L

max.
min.

G
C

max.
min.

B
max.

9
8
7

Overall
height

6
5
4
3
2

Width
across
corners

Thread

length

Height of
Height of
parallel cap nut body
portion

10

11

Compliance with a British Standard does cannot confer immunity
from legal obligations.

Part
Width across flats
reference

Table 7 — Dimensions and part references of hexagon cap nuts (A 213 and A 214)

in UNF

5/
16

1

/4 in UNF

3) Obtainable

in

Summary of pages
This document comprises a front cover, an inside front cover, pages i to vi,
pages 1 to 31 and a back cover.
This standard has been updated (see copyright date) and may have had
amendments incorporated. This will be indicated in the amendment table on the
inside front cover.
Nominal size

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
BS 3A 125 to 3A 132, 3A 136 to 3A 143,
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 147
to 3A
3A 180,
3A
3A 186,
3A200,
193,
3A201,
200,
3A168,
201,
to 181,
2A 216:1981
3A 193, 3A

3A
2A
213
to2A
2A213
216:1981+A1:2013
3A 187, 3A 192, 3A 193, 3A 200, 3A 201,
2A 213 to 2A 216:1981

© BSI
BSI
2010
©
The 2010
British Standards Institution 2013

1

from the Society of British Aerospace Companies, 29 King Street, St. James’s,
London, SW1.
v
13
13

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The


Table 8 — Dimensions and part references or ordinary and thin double-lug fixed anchor
nuts (A 136 to A 143, A 186 and A 187)
BS 2870, Rolled copper and copper alloys. Sheet, strip and foil.

BS 2874, Copper and copper alloys. Rods and sections (other than forging
stock).
BS 3488, Technical anhydrous lanolin.
A 102, Steel bolts (Unified hexagons and Unified threads) for aircraft.
A 104, Corrosion-resisting steel bolts (Unified hexagons and Unified threads)
for aircraft.
A 169, Aluminium alloy bolts (Unified hexagons and Unified threads) for
aircraft.
B 11, Brass bars suitable to be brazed or silver soldered.
L 80, Sheet and strip of aluminium-21/4 per cent magnesium alloy (soft-0).

in

No. 4-40 UNC
No. 6-32 UNC
No. 8-32 UNC
No. 10-32 UNF
1
/4 in UNF
5
/16 in UNF
3
/8 in UNF
7
/16 in UNF
1/ in UNF
2

0.1120
0.1380

0.1640
0.1900
0.2500
0.3125
0.3750
0.4375
0.5000

a
Distance of rivet
holes from centre line

Thin nut

Ordinary nut

Thin nut

Ordinary nut

Part reference

L 81, Sheet and strip of aluminium-21/4 per cent magnesium alloy
NOTE 1 For convenience ordinary
nuts only are illustrated.
(three-quarter
hard-H6).
NOTE 2 The nut body shall be round or hexagonal and shall either be made in one piece with the baseplate or be joined to it
L 163, Specification for sheet and strip of aluminium-coated
by welding or brazing.

aluminium-copper-magnesium-silicon-manganese alloy (solution treated, cold
1
2
3
4
5
6
7
8
9
10
11
worked
for flattening
and aged
at room
temperature)
Thread length
Overall height
Diameter or
Diameter of
Nominal size
(Cu 4.4, Mg
0.5, across
Si 0.8, Mn 0.8).
G
L
width
rivet holes
flats

of
nutfor bars and extruded sections of
L 168, Specification
body
aluminium-copper-magnesium-silicon-manganese
alloy (solution treated and
artificially aged) (not exceeding 200 mm diameter or minor sectional
dimension).
S 80, Specification for high chromium-nickel corrosion-resisting steel billets,
bars, forgings and parts (880–1 080 MPa; limiting ruling section 100 mm).
B
N
S 92, Carbon-manganese
steel (suitable
for
welding).
max.
min.
min.
min.
max.
max.
M
min.
max.
in
in
in
in
in

in
in
in
steel.
S 95, 11/2 perin cent nickel-chromium-molybdenum
A
0.188 0.183 0.095 0.063 0.233 0.201 0.220 0.065 0.070
SB112, Semi-free
cutting 0.115
carbon 0.079
steel, bright
for machining
0.250 0.245
0.273bars
0.237
0.250 (primarily
0.065 0.070
intended
for
the
manufacture
of
nuts).
C
0.312 0.307 0.145 0.103 0.333 0.291 0.300 0.096 0.101
SD113, “40”
carbon
steel bright
for machining
(primarily

the
0.344
0.339
0.157 bars
0.113
0.343 0.299
0.325 intended
0.096 for
0.101
manufacture
of nuts).
E
0.438
0.431 0.190 0.123 0.398 0.331 0.375 0.096 0.101
SG114, Manganese-molybeenum
steel. 0.468 0.384 0.425 0.128 0.133
0.500 0.493 0,240 0.156
0.562
0.302
SJ 117, 1 per
cent 0.554
chromium
steel.0.198 0.548 0.444 0.475 0.128 0.133
L
0.688
0.679
0.365
0.240 0.628 corrosion-resisting
0.503 0.550 0.128
0.133

S 137, Specification for high chromium-nickel
steel bright
N
0.750
0.741
0.427
0.281
0.718
0.572
0.600
0.128
bars (free machining) (880–1 080 MPa; limiting ruling section 70 mm). 0.133

a
Thread axis to be within 0.006 in of specified
position and rivet holes to be within 0.0015 in of specified position: to be inspected
steel billets, bars, forgings
S 154,specified
21/2 per
with a gauge of the relevant dimensions
in cent
Tablenickel-chromium-molybdenum
15.

1

Nominal size

in

No. 4-40 UNC
No. 6-32 UNC
No. 8-32 UNC
No. 10-32 UNF
1
/4 in UNF
5
/16 in UNF
3
/8 in UNF
7
/16 in UNF
1/ in UNF
2
14
iv
14

and parts (880–1 080 MPa: limiting ruling section 150 mm).
2
12
13
14
15
16
17
18
19
20
S 510, Carbon steel sheet and strip (430–540 MN/m2) (suitable for welding).

Length of
Width of Thickness of
Radius Radius
Counterbore
base
plate
base plate
S 511, Deep
drawing
carbon
steelbase
sheetplate
and strip (280–400 MN/m2) (suitable
for welding).
Depth
Diameter
O 18/10 chromium-nickel corrosion-resisting steel sheet and strip
S 526, Softened
P
E
R
S
Q
D
(for ref. only)
(titanium
stabilized: 54 hbar).
–0
max.18/10 chromium-nickel
max.

max.
min.
max. steel
min.sheet
min.
max.
S 527, Softened
corrosion-resisting
and strip
+0.005
(niobium stabilized:
54 hbar).
in
in
in
in
in
in
in
in
in
A b) Ministry
0.613
0.058 0.035 0.080 0.127 0.035 0.118 0.128
of Defence0.220
specifications
B AD 114,0.673
0.290 qualification
0.058 0.035approval
0.080 0.168

0.035
0.144 0.154
Design requirements,
tests and
acceptance
test
2)
C for AGS0.843
0.360
0.058
0.035
0.115
0.208
0.035
0.170 0.180
2000 series stiffnuts (BA and BSF threads) .
D DEF 151,
0.893
0.058
0.115 alloys.
0.225 0.035 0.196 0.206
Anodizing of0.390
aluminium
and0.035
aluminium
E
0.993
0.505
0.058 0.035 0.115 0.278 0.048 0.256 0.266
DEF 2331, Protective PX-1, dyed and undyed.

G
1.163
0.577
0.058 0.035 0.150 0.314 0.048 0.319 0.329
tin. 0.150 0.350 0.048 0.381 0.391
J DEF STAN,
1.26303-8 Electro-deposition
0.650
0.058of 0.035
L
1.413
0.794
0.058 0.035 0.150 0.422 0.048 0.444 0.454
NReferred to1.513
0.866
0.058 0.035 0.150 0.458 0.048 0.506 0.516
2)
in foreword only.
Part
reference

Licensed
LicensedCopy:
Copy:Mr.
Mr.John
JohnDevaney,
Devaney,British
BritishStandards
StandardsInstitution,
Institution,27/07/2012

27/07/201210:58,
10:58,Uncontrolled
UncontrolledCopy,
Copy,(c)
(c)The
TheBritish
BritishStandards
StandardsInstitution
Institution2012
2012

BS
BS 3A
3A 125
125 to
to 3A
3A 132,
132, 3A
3A 136
136 to
to 3A
3A 143,
143, 3A
3A 147
147 to
to
3A
168,
3A
180,

3A
181,
3A
186,
3A
187,
3A
192,
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A
216:1981
3A 193,
193, 3A
3A 200,
200, 3A
3A 201,
201, 2A
2A 213
213 to
to 2A
2A 216:1981
216:1981+A1:2013

0.1120
0.1380
0.1640
0.1900
0.2500
0.3125
0.3750

0.4375
0.5000

© BSI
BSI 2010
2010
©
© The British Standards Institution
2013


Table 9 — Dimensions and part references of double-lug fixed anchor cap nuts (A 215 and A 216)
DEF STAN, 03-9 Electro-deposition of silver.
DTD 10, High nickel copper alloy sheets and strips.
DTD 417, Lubricating oil, aircraft controls: anti-freezing.
DTD 904, Cadmium plating.
c) Society of British Aerospace Companies (SBAC) publication 3)
RS 732, Manufacturers identification monograms for aerospace fasteners.
This publication does not purport to include all the necessary provisions of a
contract. Users are responsible for its correct application.
Compliance with a British Standard does cannot confer immunity
from legal obligations.

Height of
parallel cap
portion

Height of nut body

L

max.

H
min.

K
max.

in

in

in

in

in

in

in

0.344
0.438
0.500

0.339
0.431
0.493

0.157
0.190
0.240

0.563
0.655
0.750

0.375
0.415
0.500

0.325
0.375
0.425

B

in
No. 10-32 UNF
1
/4 in UNF
5/
16 in UNF

0.190
0.250
0.3125

D

E
G

0.463
0.545
0.630

a
Distance
of rivet holes
from centre line

Overall height

min.

G
min.

M

max.

Part reference

Thread length

NOTE The nut body shall be round or hexagonal and shall either be made in one piece with the baseplate or be joined to it by
welding or brazing.
1

2
3
4
5
6
7
8
9
10
11
Nominal size
Diameter or
Diameter of
width across
rivet holes
flats of nut body

N
min.

max.

in

in

0.096
0.096
0.128

0.101
0.101
0.133

2

in
No. 10-32 UNF
1/ in UNF
4
5/
16 in UNF

0.190
0.250
0.3125

12

13
Width of baseplate
(for ref. only)

1
Nominal size

Length of baseplate
(for ref. only)

a

Thread axis to be within 0.006 in of specified position, and rivet holes to be within 0.0015 in of specified position: to be inspected
with a gauge of the relevant dimensions specified in Table 15.

Part reference

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A200,
193,3A
3A201,
200,2A
3A213
201,
to 2A 216:1981
3A 193, 3A
to2A
2A213
216:1981+A1:2013

O

P

14
15
Thickness of
base plate

16
Radius

17
Radius

E

R

S

18

19
20
Counterbore
Depth
Diameter

Q

D

Summary of pages
–0
max.
min.
min.
max.

max.
max.
max.
min.
This document comprises a front cover, an +0.005
inside front cover, pages i to vi,
in and ain
in
in
in
in
in
in
in
pages 1 to 31
back cover.
D
0.893
0.390
0.058
0.035
0.115
0.225
0.035
0.196
0.206
This
standard
has
been updated

(see
copyright
date)
and may
have0.256
had 0.266
E
0.993
0.505
0.058
0.035
0.115
0.278
0.048
amendments
incorporated.
This will
be indicated
in0.314
the amendment
table on
the
G
1.163
0.577
0.058
0.035
0.150
0.048
0.319

0.329
inside front cover.

3) Obtainable

from the Society of British Aerospace Companies, 29 King Street, St. James’s,
London, SW1.

© BSI
BSI
2010
©
The 2010
British Standards Institution 2013

v
15


L 81, Sheet and strip of aluminium-21/4 per cent magnesium alloy
(three-quarter hard-H6).
L 163, Specification for sheet and strip of aluminium-coated
aluminium-copper-magnesium-silicon-manganese alloy (solution treated, cold
worked for flattening and aged at room temperature)
(Cu 4.4, Mg 0.5, Si 0.8, Mn 0.8).
L 168, Specification for bars and extruded sections of
aluminium-copper-magnesium-silicon-manganese alloy (solution treated and
artificially aged) (not exceeding 200 mm diameter or minor sectional
dimension).
S 80, Specification for high chromium-nickel corrosion-resisting steel billets,

bars, forgings and parts (880–1 080 MPa; limiting ruling section 100 mm).
S 92, Carbon-manganese steel (suitable for welding).
S 95, 11/2 per cent nickel-chromium-molybdenum steel.

S 112, Semi-free cutting carbon steel, bright bars for machining (primarily
intended for the manufacture of nuts).
S 113, “40” carbon steel bright bars for machining (primarily intended for the
manufacture of nuts).
S 114, Manganese-molybeenum steel.
S 117, 1 per cent chromium steel.
S 137, Specification for high chromium-nickel corrosion-resisting steel bright
bars (free machining) (880–1 080 MPa; limiting ruling section 70 mm).
S 154, 21/2 per cent nickel-chromium-molybdenum steel billets, bars, forgings
and parts (880–1 080 MPa: limiting ruling section 150 mm).
S 510, Carbon steel sheet and strip (430–540 MN/m2) (suitable for welding).
S 511, Deep drawing carbon steel sheet and strip (280–400 MN/m2) (suitable
for welding).
S 526, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(titanium stabilized: 54 hbar).
S 527, Softened 18/10 chromium-nickel corrosion-resisting steel sheet and strip
(niobium stabilized: 54 hbar).
b) Ministry of Defence specifications
AD 114, Design requirements, qualification approval tests and acceptance test
for AGS 2000 series stiffnuts (BA and BSF threads)2).
DEF 151, Anodizing of aluminium and aluminium alloys.
DEF 2331, Protective PX-1, dyed and undyed.
DEF STAN, 03-8 Electro-deposition of tin.
2)

iv

16

NOTE 1 For convenience ordinary nuts only are illustrated.
NOTE 2 The nut body shall be round or hexagonal and shall either be made in one piece with the baseplate or be joined to it by welding or brazing. Thread axis to be
within 0.006 in of specified position: to be inspected with a gauge of the relevant dimensions specified in Table 17.
NOTE 3 All dimensions are in inches.

BS 2870, Rolled copper and copper alloys. Sheet, strip and foil.
BS 2874, Copper and copper alloys. Rods and sections (other than forging
stock).
BS 3488, Technical anhydrous lanolin.
A 102, Steel bolts (Unified hexagons and Unified threads) for aircraft.
A 104, Corrosion-resisting steel bolts (Unified hexagons and Unified threads)
for aircraft.
A 169, Aluminium alloy bolts (Unified hexagons and Unified threads) for
aircraft.
B 11, Brass bars suitable to be brazed or silver soldered.
L 80, Sheet and strip of aluminium-21/4 per cent magnesium alloy (soft-0).

Table 10 — Dimensions and part references of ordinary and thin double-lug floating anchor
nuts (A 147 to A 156, A 192 and A 193)

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
BS 3A 125 to 3A 132, 3A 136 to 3A 143,
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 147 to 3A 168, 3A 180, 3A 181, 3A 186,
3A 193, 3A 200, 3A 201, 2A 213 to 2A 216:1981
216:1981+A1:2013

3A 187, 3A 192, 3A 193, 3A 200, 3A 201,
2A 213 to 2A 216:1981

Referred to in foreword only.

© BSI
BSI 2010
2010
©
© The British Standards Institution
2013

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The


from the Society of British Aerospace Companies, 29 King Street, St. James’s,
London, SW1.

No. 6-32 UNC
No. 8-32 UNC
No. 10-32 UNF
1/
4 in UNF
5/
16 in UNF
3/
8 in UNF

a

0.2500
0.3125
0.3750

0.1380
0.1640
0.1900

2

B
C
D
E
G
J

E
G
J

B
C
D

4

20

0.2500

0.3120
0.3440
0.438
0.500
0.562

in

max.

B

0,375
0.425
0.475

0.250
0.300
0.325

in

M

6

Thread length
G

5

22

21

23

0.079
0.103
0.113
0.123
0.156
0.198

in

min.

0.096
0.128
0.128

0.065
0.096
0.096

in

min.

in

max.

0.101
0.133
0.133

0.070
0.101
0.101

N

0.993
1.163
1.263

0.673
0.843
0.893

in

max.

O

Diameter of rivet Length
holes

(for ref.
only)

0.115
0.145
0.157
0.190
0.240
0.302

in

in

0.245
0.307
0.339
0.431
0.493
0.554

min.

min.

Diameter or
width across flats
of nut body

3

8

0.115
0.150
0.150

0.080
0.115
0.115

in

–0
+0.005

R

Radius

24

0.327
0.399
0.435
0.543
0.605
0.668

in

max.

P

9

X

0.268
0.283
0.324

0.098
0.128
0.158

in

nom.

26

0.398
0.496
0.516
0.646
0.714
0.814

in

max.

F

27

0.393
0.491
0.511
0.641
0.709
0.809

in

min.

0.056
0.072
0.072

0.056
0.056
0.056

in

nom.

U

Width

0.056
0.072
0.072

0.056
0.056
0.056

in

nom.

V

Depth

Indentation
(optional)

Attachment plate
Radius

25

0.322

0.394
0.430
0.538
0.600
0.663

in

min.

10

Length of
baseplate

Nut and baseplate
Width of baseplate

7

11a

28a

0.026
0.034
0.034
0.034
0.034
0.034

in

min.

0.568
0.630
0.693

0.352
0.424
0.460

in

min.

Q

0.094
0.098
0.103

0.068
0.076
0.081

in

min.

C

Width Depth
of
of lug
channel

28

0.048
0.048
0.048
0.048
0.048
0.048

in

max.

E

Thickness of
baseplate

11

13

in
—
—
0.324
0.383
0.463
0.533
29

in
0.177
0.226
0.252
0.312
0.375
0.437
28b

A

0.075
0.080
0.085

0.065
0.070
0.075

in

0.003

a

30

0.119
0.125
0.140
0.135
0.163
0.163

in

nom.

S

Radius

14

31

0.424
0.496
0.532
0.640
0.720

0.780

in

max.

W

Width

15

17

32

0.438
0.541
0.561
0.701
0.769
0.869

in

max.

K
min.

Length

16

33

0.423
0.526
0.546
0.686
0.754
0.854

in

H

0.078
0.078
0.078

0.078
0.078
0.078

in

max.

0.300

0.362
0.425

0.305
0.367
0.430

in
0.178
0 209
0.235

max.
in

Y

0.173
0.204
0.230

min.

0.419
0.497
0.577

0.285
0.353
0.363

in

max.

in

max.

0.352
0.413
0.473

0.249
0.311
0.319

18

18a

Assembly

35

0.163
0.181
0.196
0.225
0.254

0.316

0.075
0.100
0.170

0.065
0.065
0.065

in

max.

0.050
0.050
0.050

0.040
0.040
0.040

in

min.

Lateral (along
rivet axis)

34

0.273
0.335
0.418
0.488
0.576
0.636

in

in

nom.

Z1

19

37

0.028
0.028
0.028
0.028
0.036
0.036

in

nom.

T

0.025
0.025
0.025

0.025
0.025
0.025

in

min.

0.030
0.030
0.030

0.030
0.030
0.030

in

max.

Transverse Axial
(across
rivet axis)

36

0.278
0.340
0.372
0.472
0.544
0.656

Float

0.005

J1

18b

DEF STAN, 03-9 Electro-deposition of silver.
DTD 10, High nickel copper alloy sheets and strips.
DTD 417, Lubricating oil, aircraft controls: anti-freezing.
DTD 904, Cadmium plating.
c) Society of British Aerospace Companies (SBAC) publication 3)
RS 732, Manufacturers identification monograms for aerospace fasteners.
This publication does not purport to include all the necessary provisions of a
contract. Users are responsible for its correct application.
in

nom.

J
and
Z

Distances

Attachment plate

Depth Diameter of hole Overall height
of
L
channel
Ord.
Thin
nut
nut

max.

min.

D

Countersink
diameter

12

Compliance with a British Standard does cannot confer immunity
from legal obligations.

Y diameter hole to be within 0.003 in of specified position and rivet holes to be within 0.0015 in of specified position: to be inspected with a gauge of the relevant dimensions specified in Table 16.

1
/4 in UNF
5
/16 in UNF
3
/8 in UNF

No. 6-32 UNC
No. 8-32 UNC
No. 10-32 UNF

in

0.1380
0.1640
0.1900
0.2500
0.3125
0.3750

Nominal size

1

in

2

Ordinary
nut

1

Part reference

Thin nut

Nominal size

Part reference

Summary of pages
This document comprises a front cover, an inside front cover, pages i to vi,
pages 1 to 31 and a back cover.
This standard has been updated (see copyright date) and may have had
amendments incorporated. This will be indicated in the amendment table on the
inside front cover.

Distance of rivet hole
from centreline

3) Obtainable
Distance

Thickness

Table 10 — Dimensions and part references of ordinary and thin double-lug floating

anchor nuts (A 147 to A 156, A 192 and A 193)

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The British Standards Institution 2012

BS 3A 125 to 3A 132, 3A 136 to 3A 143, 3A 147 to
BS 3A 125 to 3A 132, 3A 136 to 3A 143,
3A 168, 3A 180, 3A 181, 3A 186, 3A 187, 3A 192,
3A 147
to 3A
3A 180,
3A
3A 186,
3A200,
193,
3A201,
200,
3A168,
201,
to 181,
2A 216:1981
3A 193, 3A
3A
2A
213
to2A
2A213
216:1981+A1:2013
3A 187, 3A 192, 3A 193, 3A 200, 3A 201,
2A 213 to 2A 216:1981

© BSI
BSI
2010
©
The 2010
British Standards Institution 2013

v
17
17

Licensed Copy: Mr. John Devaney, British Standards Institution, 27/07/2012 10:58, Uncontrolled Copy, (c) The